21479081509 has 2 divisors, whose sum is σ = 21479081510. Its totient is φ = 21479081508.

The previous prime is 21479081501. The next prime is 21479081527. The reversal of 21479081509 is 90518097412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20383272900 + 1095808609 = 142770^2 + 33103^2 .

It is a cyclic number.

It is not a de Polignac number, because 21479081509 - 2³ = 21479081501 is a prime.

It is a super-2 number, since 2×21479081509² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21479081501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10739540754 + 10739540755.

It is an arithmetic number, because the mean of its divisors is an integer number (10739540755).

Almost surely, 2^21479081509 is an apocalyptic number.

It is an amenable number.

21479081509 is a deficient number, since it is larger than the sum of its proper divisors (1).

21479081509 is an equidigital number, since it uses as much as digits as its factorization.

21479081509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 181440, while the sum is 46.

The spelling of 21479081509 in words is "twenty-one billion, four hundred seventy-nine million, eighty-one thousand, five hundred nine".