2155239525978 has 144 divisors (see below), whose sum is σ = 6237799532640. Its totient is φ = 530339140800.

The previous prime is 2155239525953. The next prime is 2155239525983. The reversal of 2155239525978 is 8795259325512.

It is a happy number.

2155239525978 is a `hidden beast` number, since 2 + 1 + 5 + 5 + 2 + 39 + 5 + 2 + 597 + 8 = 666.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 5661553 + ... + 6030228.

It is an arithmetic number, because the mean of its divisors is an integer number (43318052310).

Almost surely, 2^{2155239525978} is an apocalyptic number.

2155239525978 is an abundant number, since it is smaller than the sum of its proper divisors (4082560006662).

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

2155239525978 is a wasteful number, since it uses less digits than its factorization.

2155239525978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11691833 (or 11691823 counting only the distinct ones).

The product of its digits is 68040000, while the sum is 63.

The spelling of 2155239525978 in words is "two trillion, one hundred fifty-five billion, two hundred thirty-nine million, five hundred twenty-five thousand, nine hundred seventy-eight".