1638628860 has 48 divisors (see below), whose sum is σ = 5005268352. Its totient is φ = 397243200.

The previous prime is 1638628843. The next prime is 1638628877. The reversal of 1638628860 is 688268361.

It is an interprime number because it is at equal distance from previous prime (1638628843) and next prime (1638628877).

It is a congruent number.

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, 1240726 + ... + 1242045.

It is an arithmetic number, because the mean of its divisors is an integer number (104276424).

Almost surely, 2^1638628860 is an apocalyptic number.

1638628860 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1638628860 is an abundant number, since it is smaller than the sum of its proper divisors (3366639492).

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

1638628860 is a wasteful number, since it uses less digits than its factorization.

1638628860 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2482794 (or 2482792 counting only the distinct ones).

The product of its (nonzero) digits is 663552, while the sum is 48.

The square root of 1638628860 is about 40479.9809782564. The cubic root of 1638628860 is about 1178.9449681192.

The spelling of 1638628860 in words is "one billion, six hundred thirty-eight million, six hundred twenty-eight thousand, eight hundred sixty".