155515999980 has 96 divisors (see below), whose sum is σ = 475115332608. Its totient is φ = 37694131200.

The previous prime is 155515999973. The next prime is 155515999993. The reversal of 155515999980 is 89999515551.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (66).

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, 4386525 + ... + 4421835.

It is an arithmetic number, because the mean of its divisors is an integer number (4949118048).

Almost surely, 2^155515999980 is an apocalyptic number.

155515999980 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

155515999980 is an abundant number, since it is smaller than the sum of its proper divisors (319599332628).

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

155515999980 is a wasteful number, since it uses less digits than its factorization.

155515999980 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42007 (or 42005 counting only the distinct ones).

The product of its (nonzero) digits is 32805000, while the sum is 66.

The spelling of 155515999980 in words is "one hundred fifty-five billion, five hundred fifteen million, nine hundred ninety-nine thousand, nine hundred eighty".