21356253747723 has 4 divisors (see below), whose sum is σ = 28475004996968. Its totient is φ = 14237502498480.

The previous prime is 21356253747683. The next prime is 21356253747733. The reversal of 21356253747723 is 32774735265312.

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

It is not a de Polignac number, because 21356253747723 - 2⁹ = 21356253747211 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21356253747733) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3559375624618 + ... + 3559375624623.

It is an arithmetic number, because the mean of its divisors is an integer number (7118751249242).

Almost surely, 2^{21356253747723} is an apocalyptic number.

21356253747723 is a deficient number, since it is larger than the sum of its proper divisors (7118751249245).

21356253747723 is an equidigital number, since it uses as much as digits as its factorization.

21356253747723 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7118751249244.

The product of its digits is 44452800, while the sum is 57.

The spelling of 21356253747723 in words is "twenty-one trillion, three hundred fifty-six billion, two hundred fifty-three million, seven hundred forty-seven thousand, seven hundred twenty-three".