1940138208 has 72 divisors (see below), whose sum is σ = 5521527648. Its totient is φ = 646213632.

The previous prime is 1940138191. The next prime is 1940138237. The reversal of 1940138208 is 8028310491.

1940138208 is a `hidden beast` number, since 19 + 401 + 38 + 208 = 666.

It is a Cunningham number, because it is equal to 44047²-1.

It is a tau number, because it is divible by the number of its divisors (72).

It is a super-2 number, since 2×1940138208² = 7528272532282902528, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 703360 + ... + 706112.

It is an arithmetic number, because the mean of its divisors is an integer number (76687884).

Almost surely, 2^1940138208 is an apocalyptic number.

1940138208 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

1940138208 is an abundant number, since it is smaller than the sum of its proper divisors (3581389440).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1940138208 is a wasteful number, since it uses less digits than its factorization.

With its successor (1940138209) it forms a Ruth-Aaron pair, since the sum of their prime factors is the same (5216).

1940138208 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5216 (or 5205 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 36.

The square root of 1940138208 is about 44046.9999886485. Note that the first 4 decimals coincide. The cubic root of 1940138208 is about 1247.2233209833.

Adding to 1940138208 its reverse (8028310491), we get a palindrome (9968448699).

The spelling of 1940138208 in words is "one billion, nine hundred forty million, one hundred thirty-eight thousand, two hundred eight".