1638405696 has 28 divisors (see below), whose sum is σ = 4334948912. Its totient is φ = 546135168.

The previous prime is 1638405683. The next prime is 1638405697. The reversal of 1638405696 is 6965048361.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is not an unprimeable number, because it can be changed into a prime (1638405697) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4266490 + ... + 4266873.

It is an arithmetic number, because the mean of its divisors is an integer number (154819604).

Almost surely, 2^1638405696 is an apocalyptic number.

1638405696 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

1638405696 is an abundant number, since it is smaller than the sum of its proper divisors (2696543216).

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

1638405696 is an equidigital number, since it uses as much as digits as its factorization.

1638405696 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8533378 (or 8533368 counting only the distinct ones).

The product of its (nonzero) digits is 933120, while the sum is 48.

The square root of 1638405696 is about 40477.2244107720. The cubic root of 1638405696 is about 1178.8914457250.

The spelling of 1638405696 in words is "one billion, six hundred thirty-eight million, four hundred five thousand, six hundred ninety-six".