21726465281 has 2 divisors, whose sum is σ = 21726465282. Its totient is φ = 21726465280.

The previous prime is 21726465269. The next prime is 21726465317. The reversal of 21726465281 is 18256462712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19779890881 + 1946574400 = 140641^2 + 44120^2 .

It is a cyclic number.

It is not a de Polignac number, because 21726465281 - 2¹⁰ = 21726464257 is a prime.

It is a super-2 number, since 2×21726465281² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21726465181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10863232640 + 10863232641.

It is an arithmetic number, because the mean of its divisors is an integer number (10863232641).

Almost surely, 2^21726465281 is an apocalyptic number.

It is an amenable number.

21726465281 is a deficient number, since it is larger than the sum of its proper divisors (1).

21726465281 is an equidigital number, since it uses as much as digits as its factorization.

21726465281 is an evil number, because the sum of its binary digits is even.

The product of its digits is 322560, while the sum is 44.

The spelling of 21726465281 in words is "twenty-one billion, seven hundred twenty-six million, four hundred sixty-five thousand, two hundred eighty-one".