155664638 has 4 divisors (see below), whose sum is σ = 233496960. Its totient is φ = 77832318.

The previous prime is 155664637. The next prime is 155664653. The reversal of 155664638 is 836466551.

155664638 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (155664637) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38916158 + ... + 38916161.

It is an arithmetic number, because the mean of its divisors is an integer number (58374240).

Almost surely, 2^155664638 is an apocalyptic number.

155664638 is a deficient number, since it is larger than the sum of its proper divisors (77832322).

155664638 is an equidigital number, since it uses as much as digits as its factorization.

155664638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77832321.

The product of its digits is 518400, while the sum is 44.

The square root of 155664638 is about 12476.5635493112. The cubic root of 155664638 is about 537.9352312590.

The spelling of 155664638 in words is "one hundred fifty-five million, six hundred sixty-four thousand, six hundred thirty-eight".