21353231371 has 4 divisors (see below), whose sum is σ = 21384960472. Its totient is φ = 21321502272.

The previous prime is 21353231329. The next prime is 21353231447. The reversal of 21353231371 is 17313235312.

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 21353231371 - 2⁹ = 21353230859 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21353231071) 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, 15863541 + ... + 15864886.

It is an arithmetic number, because the mean of its divisors is an integer number (5346240118).

Almost surely, 2^21353231371 is an apocalyptic number.

21353231371 is a deficient number, since it is larger than the sum of its proper divisors (31729101).

21353231371 is an equidigital number, since it uses as much as digits as its factorization.

21353231371 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31729100.

The product of its digits is 11340, while the sum is 31.

Adding to 21353231371 its reverse (17313235312), we get a palindrome (38666466683).

The spelling of 21353231371 in words is "twenty-one billion, three hundred fifty-three million, two hundred thirty-one thousand, three hundred seventy-one".