1638364638 has 16 divisors (see below), whose sum is σ = 3277758096. Its totient is φ = 545950080.

The previous prime is 1638364621. The next prime is 1638364667. The reversal of 1638364638 is 8364638361.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21333 + ... + 61088.

It is an arithmetic number, because the mean of its divisors is an integer number (204859881).

Almost surely, 2^1638364638 is an apocalyptic number.

1638364638 is an abundant number, since it is smaller than the sum of its proper divisors (1639393458).

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

1638364638 is a wasteful number, since it uses less digits than its factorization.

1638364638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85739.

The product of its digits is 1492992, while the sum is 48.

The square root of 1638364638 is about 40476.7172334912. The cubic root of 1638364638 is about 1178.8815980767.

The spelling of 1638364638 in words is "one billion, six hundred thirty-eight million, three hundred sixty-four thousand, six hundred thirty-eight".