21029372161 has 4 divisors (see below), whose sum is σ = 24033568192. Its totient is φ = 18025176132.

The previous prime is 21029372149. The next prime is 21029372201. The reversal of 21029372161 is 16127392012.

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 21029372161 - 2⁵ = 21029372129 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21029372131) 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, 1502098005 + ... + 1502098018.

It is an arithmetic number, because the mean of its divisors is an integer number (6008392048).

Almost surely, 2^21029372161 is an apocalyptic number.

It is an amenable number.

21029372161 is a deficient number, since it is larger than the sum of its proper divisors (3004196031).

21029372161 is an equidigital number, since it uses as much as digits as its factorization.

21029372161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3004196030.

The product of its (nonzero) digits is 9072, while the sum is 34.

The spelling of 21029372161 in words is "twenty-one billion, twenty-nine million, three hundred seventy-two thousand, one hundred sixty-one".