21369656163 has 4 divisors (see below), whose sum is σ = 28492874888. Its totient is φ = 14246437440.

The previous prime is 21369656129. The next prime is 21369656167. The reversal of 21369656163 is 36165696312.

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

It is not a de Polignac number, because 21369656163 - 2¹² = 21369652067 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21369656167) 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, 3561609358 + ... + 3561609363.

It is an arithmetic number, because the mean of its divisors is an integer number (7123218722).

Almost surely, 2^21369656163 is an apocalyptic number.

21369656163 is a deficient number, since it is larger than the sum of its proper divisors (7123218725).

21369656163 is an equidigital number, since it uses as much as digits as its factorization.

21369656163 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7123218724.

The product of its digits is 1049760, while the sum is 48.

The spelling of 21369656163 in words is "twenty-one billion, three hundred sixty-nine million, six hundred fifty-six thousand, one hundred sixty-three".