172121015550 has 96 divisors (see below), whose sum is σ = 477023468544. Its totient is φ = 40708576000.

The previous prime is 172121015533. The next prime is 172121015567. The reversal of 172121015550 is 55510121271.

It is an interprime number because it is at equal distance from previous prime (172121015533) and next prime (172121015567).

It is a Harshad number since it is a multiple of its sum of digits (30).

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 47 ways as a sum of consecutive naturals, for example, 1204494 + ... + 1339793.

It is an arithmetic number, because the mean of its divisors is an integer number (4968994464).

Almost surely, 2^172121015550 is an apocalyptic number.

172121015550 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

172121015550 is an abundant number, since it is smaller than the sum of its proper divisors (304902452994).

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

172121015550 is a wasteful number, since it uses less digits than its factorization.

172121015550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2544354 (or 2544349 counting only the distinct ones).

The product of its (nonzero) digits is 3500, while the sum is 30.

The spelling of 172121015550 in words is "one hundred seventy-two billion, one hundred twenty-one million, fifteen thousand, five hundred fifty".