21373462075721 has 4 divisors (see below), whose sum is σ = 24426813800832. Its totient is φ = 18320110350612.

The previous prime is 21373462075687. The next prime is 21373462075759. The reversal of 21373462075721 is 12757026437312.

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 not a de Polignac number, because 21373462075721 - 2³⁰ = 21372388333897 is a prime.

It is a super-2 number, since 2×21373462075721² (a number of 27 digits) contains 22 as substring.

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 21373462075721.

It is not an unprimeable number, because it can be changed into a prime (21373462075321) 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, 1526675862545 + ... + 1526675862558.

It is an arithmetic number, because the mean of its divisors is an integer number (6106703450208).

Almost surely, 2^{21373462075721} is an apocalyptic number.

It is an amenable number.

21373462075721 is a deficient number, since it is larger than the sum of its proper divisors (3053351725111).

21373462075721 is an equidigital number, since it uses as much as digits as its factorization.

21373462075721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3053351725110.

The product of its (nonzero) digits is 2963520, while the sum is 50.

The spelling of 21373462075721 in words is "twenty-one trillion, three hundred seventy-three billion, four hundred sixty-two million, seventy-five thousand, seven hundred twenty-one".