172890428891 has 4 divisors (see below), whose sum is σ = 172903328232. Its totient is φ = 172877529552.

The previous prime is 172890428863. The next prime is 172890428939. The reversal of 172890428891 is 198824098271.

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

It is a cyclic number.

It is not a de Polignac number, because 172890428891 - 2⁶ = 172890428827 is a prime.

It is a super-2 number, since 2×172890428891² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 172890428891.

It is not an unprimeable number, because it can be changed into a prime (172890728891) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6429545 + ... + 6456378.

It is an arithmetic number, because the mean of its divisors is an integer number (43225832058).

Almost surely, 2^172890428891 is an apocalyptic number.

172890428891 is a deficient number, since it is larger than the sum of its proper divisors (12899341).

172890428891 is a wasteful number, since it uses less digits than its factorization.

172890428891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12899340.

The product of its (nonzero) digits is 4644864, while the sum is 59.

The spelling of 172890428891 in words is "one hundred seventy-two billion, eight hundred ninety million, four hundred twenty-eight thousand, eight hundred ninety-one".