21106731535 has 4 divisors (see below), whose sum is σ = 25328077848. Its totient is φ = 16885385224.

The previous prime is 21106731523. The next prime is 21106731577. The reversal of 21106731535 is 53513760112.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21106731535 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21106731535.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2110673149 + ... + 2110673158.

It is an arithmetic number, because the mean of its divisors is an integer number (6332019462).

Almost surely, 2^21106731535 is an apocalyptic number.

21106731535 is a deficient number, since it is larger than the sum of its proper divisors (4221346313).

21106731535 is an equidigital number, since it uses as much as digits as its factorization.

21106731535 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4221346312.

The product of its (nonzero) digits is 18900, while the sum is 34.

The spelling of 21106731535 in words is "twenty-one billion, one hundred six million, seven hundred thirty-one thousand, five hundred thirty-five".