21726871297 has 2 divisors, whose sum is σ = 21726871298. Its totient is φ = 21726871296.

The previous prime is 21726871259. The next prime is 21726871321. The reversal of 21726871297 is 79217862712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21668134401 + 58736896 = 147201^2 + 7664^2 .

It is a cyclic number.

It is not a de Polignac number, because 21726871297 - 2⁷ = 21726871169 is a prime.

It is not a weakly prime, because it can be changed into another prime (21726871597) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10863435648 + 10863435649.

It is an arithmetic number, because the mean of its divisors is an integer number (10863435649).

Almost surely, 2^21726871297 is an apocalyptic number.

It is an amenable number.

21726871297 is a deficient number, since it is larger than the sum of its proper divisors (1).

21726871297 is an equidigital number, since it uses as much as digits as its factorization.

21726871297 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1185408, while the sum is 52.

The spelling of 21726871297 in words is "twenty-one billion, seven hundred twenty-six million, eight hundred seventy-one thousand, two hundred ninety-seven".