1638157056 has 144 divisors (see below), whose sum is σ = 4560245760. Its totient is φ = 521441280.

The previous prime is 1638157039. The next prime is 1638157063. The reversal of 1638157056 is 6507518361.

It is a junction number, because it is equal to n+sod(n) for n = 1638156999 and 1638157017.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1975650 + ... + 1976478.

Almost surely, 2^1638157056 is an apocalyptic number.

1638157056 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1638157056, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2280122880).

1638157056 is an abundant number, since it is smaller than the sum of its proper divisors (2922088704).

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

1638157056 is an equidigital number, since it uses as much as digits as its factorization.

1638157056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 962 (or 948 counting only the distinct ones).

The product of its (nonzero) digits is 151200, while the sum is 42.

The square root of 1638157056 is about 40474.1529373994. The cubic root of 1638157056 is about 1178.8318075864.

It can be divided in two parts, 16381 and 57056, that added together give a palindrome (73437).

The spelling of 1638157056 in words is "one billion, six hundred thirty-eight million, one hundred fifty-seven thousand, fifty-six".