1638047940 has 48 divisors (see below), whose sum is σ = 4601240448. Its totient is φ = 435412224.

The previous prime is 1638047909. The next prime is 1638047941. The reversal of 1638047940 is 497408361.

It is a junction number, because it is equal to n+sod(n) for n = 1638047892 and 1638047901.

It is not an unprimeable number, because it can be changed into a prime (1638047941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 24832 + ... + 62391.

It is an arithmetic number, because the mean of its divisors is an integer number (95859176).

Almost surely, 2^1638047940 is an apocalyptic number.

1638047940 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1638047940 is an abundant number, since it is smaller than the sum of its proper divisors (2963192508).

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

1638047940 is a wasteful number, since it uses less digits than its factorization.

1638047940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 87548 (or 87546 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 42.

The square root of 1638047940 is about 40472.8049435667. The cubic root of 1638047940 is about 1178.8056334034.

The spelling of 1638047940 in words is "one billion, six hundred thirty-eight million, forty-seven thousand, nine hundred forty".