21479079521 has 2 divisors, whose sum is σ = 21479079522. Its totient is φ = 21479079520.

The previous prime is 21479079499. The next prime is 21479079533. The reversal of 21479079521 is 12597097412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14151719521 + 7327360000 = 118961^2 + 85600^2 .

It is a cyclic number.

It is not a de Polignac number, because 21479079521 - 2¹⁰ = 21479078497 is a prime.

It is a super-2 number, since 2×21479079521² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21479079551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10739539760 + 10739539761.

It is an arithmetic number, because the mean of its divisors is an integer number (10739539761).

Almost surely, 2^21479079521 is an apocalyptic number.

It is an amenable number.

21479079521 is a deficient number, since it is larger than the sum of its proper divisors (1).

21479079521 is an equidigital number, since it uses as much as digits as its factorization.

21479079521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 317520, while the sum is 47.

The spelling of 21479079521 in words is "twenty-one billion, four hundred seventy-nine million, seventy-nine thousand, five hundred twenty-one".