21373473573721 has 16 divisors (see below), whose sum is σ = 22334382222336. Its totient is φ = 20415204524176.

The previous prime is 21373473573713. The next prime is 21373473573731. The reversal of 21373473573721 is 12737537437312.

It is a cyclic number.

It is not a de Polignac number, because 21373473573721 - 2³ = 21373473573713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21373473573701) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 292578426 + ... + 292651468.

It is an arithmetic number, because the mean of its divisors is an integer number (1395898888896).

Almost surely, 2^{21373473573721} is an apocalyptic number.

It is an amenable number.

21373473573721 is a deficient number, since it is larger than the sum of its proper divisors (960908648615).

21373473573721 is a wasteful number, since it uses less digits than its factorization.

21373473573721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90932.

The product of its digits is 15558480, while the sum is 55.

The spelling of 21373473573721 in words is "twenty-one trillion, three hundred seventy-three billion, four hundred seventy-three million, five hundred seventy-three thousand, seven hundred twenty-one".