21012611161 has 4 divisors (see below), whose sum is σ = 21122625024. Its totient is φ = 20902597300.

The previous prime is 21012611153. The next prime is 21012611209. The reversal of 21012611161 is 16111621012.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21012611161 - 2³ = 21012611153 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21012611261) 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, 55006645 + ... + 55007026.

It is an arithmetic number, because the mean of its divisors is an integer number (5280656256).

Almost surely, 2^21012611161 is an apocalyptic number.

It is an amenable number.

21012611161 is a deficient number, since it is larger than the sum of its proper divisors (110013863).

21012611161 is a wasteful number, since it uses less digits than its factorization.

21012611161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 110013862.

The product of its (nonzero) digits is 144, while the sum is 22.

The spelling of 21012611161 in words is "twenty-one billion, twelve million, six hundred eleven thousand, one hundred sixty-one".