1639393992 has 40 divisors (see below), whose sum is σ = 4591822950. Its totient is φ = 546464448.

The previous prime is 1639393969. The next prime is 1639393999. The reversal of 1639393992 is 2993939361.

It is a happy number.

1639393992 is a `hidden beast` number, since 163 + 9 + 393 + 9 + 92 = 666.

It can be written as a sum of positive squares in only one way, i.e., 1266363396 + 373030596 = 35586^2 + 19314^2 .

It is a super-2 number, since 2×1639393992² = 5375225322011392128, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (1639393999) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 1264317 + ... + 1265612.

Almost surely, 2^1639393992 is an apocalyptic number.

1639393992 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

1639393992 is an abundant number, since it is smaller than the sum of its proper divisors (2952428958).

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

1639393992 is a wasteful number, since it uses less digits than its factorization.

1639393992 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2529947 (or 2529934 counting only the distinct ones).

The product of its digits is 2125764, while the sum is 54.

The square root of 1639393992 is about 40489.4306208423. The cubic root of 1639393992 is about 1179.1284361761.

The spelling of 1639393992 in words is "one billion, six hundred thirty-nine million, three hundred ninety-three thousand, nine hundred ninety-two".