21039079697 has 2 divisors, whose sum is σ = 21039079698. Its totient is φ = 21039079696.

The previous prime is 21039079693. The next prime is 21039079739. The reversal of 21039079697 is 79697093012.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20883429121 + 155650576 = 144511^2 + 12476^2 .

It is a cyclic number.

It is not a de Polignac number, because 21039079697 - 2² = 21039079693 is a prime.

It is a super-2 number, since 2×21039079697² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21039079693) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10519539848 + 10519539849.

It is an arithmetic number, because the mean of its divisors is an integer number (10519539849).

Almost surely, 2^21039079697 is an apocalyptic number.

It is an amenable number.

21039079697 is a deficient number, since it is larger than the sum of its proper divisors (1).

21039079697 is an equidigital number, since it uses as much as digits as its factorization.

21039079697 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1285956, while the sum is 53.

The spelling of 21039079697 in words is "twenty-one billion, thirty-nine million, seventy-nine thousand, six hundred ninety-seven".