1638385880 has 32 divisors (see below), whose sum is σ = 3903215040. Its totient is φ = 616803840.

The previous prime is 1638385843. The next prime is 1638385883. The reversal of 1638385880 is 885838361.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1638385883) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1204016 + ... + 1205375.

It is an arithmetic number, because the mean of its divisors is an integer number (121975470).

Almost surely, 2^1638385880 is an apocalyptic number.

1638385880 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1638385880 is an abundant number, since it is smaller than the sum of its proper divisors (2264829160).

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

1638385880 is a wasteful number, since it uses less digits than its factorization.

1638385880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2409419 (or 2409415 counting only the distinct ones).

The product of its (nonzero) digits is 1105920, while the sum is 50.

The square root of 1638385880 is about 40476.9796304023. The cubic root of 1638385880 is about 1178.8866929325.

The spelling of 1638385880 in words is "one billion, six hundred thirty-eight million, three hundred eighty-five thousand, eight hundred eighty".