1638225885 has 32 divisors (see below), whose sum is σ = 2767973760. Its totient is φ = 825078528.

The previous prime is 1638225877. The next prime is 1638225947. The reversal of 1638225885 is 5885228361.

It is not a de Polignac number, because 1638225885 - 2³ = 1638225877 is a prime.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 81279 + ... + 99411.

It is an arithmetic number, because the mean of its divisors is an integer number (86499180).

Almost surely, 2^1638225885 is an apocalyptic number.

1638225885 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1638225885 is a deficient number, since it is larger than the sum of its proper divisors (1129747875).

1638225885 is a wasteful number, since it uses less digits than its factorization.

1638225885 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18477.

The product of its digits is 921600, while the sum is 48.

The square root of 1638225885 is about 40475.0032118590. The cubic root of 1638225885 is about 1178.8483173339.

The spelling of 1638225885 in words is "one billion, six hundred thirty-eight million, two hundred twenty-five thousand, eight hundred eighty-five".