21210571161 has 12 divisors (see below), whose sum is σ = 32994221988. Its totient is φ = 13052659104.

The previous prime is 21210571157. The next prime is 21210571177. The reversal of 21210571161 is 16117501212.

21210571161 is a `hidden beast` number, since 21 + 2 + 10 + 571 + 1 + 61 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 13672858761 + 7537712400 = 116931^2 + 86820^2 .

It is not a de Polignac number, because 21210571161 - 2² = 21210571157 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21210571111) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 90643350 + ... + 90643583.

It is an arithmetic number, because the mean of its divisors is an integer number (2749518499).

Almost surely, 2^21210571161 is an apocalyptic number.

It is an amenable number.

21210571161 is a deficient number, since it is larger than the sum of its proper divisors (11783650827).

21210571161 is a wasteful number, since it uses less digits than its factorization.

21210571161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 181286952 (or 181286949 counting only the distinct ones).

The product of its (nonzero) digits is 840, while the sum is 27.

The spelling of 21210571161 in words is "twenty-one billion, two hundred ten million, five hundred seventy-one thousand, one hundred sixty-one".