11525721281 has 2 divisors, whose sum is σ = 11525721282. Its totient is φ = 11525721280.

The previous prime is 11525721241. The next prime is 11525721299. The reversal of 11525721281 is 18212752511.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11004010000 + 521711281 = 104900^2 + 22841^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-11525721281 is a prime.

It is a super-2 number, since 2×11525721281² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (11525721241) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5762860640 + 5762860641.

It is an arithmetic number, because the mean of its divisors is an integer number (5762860641).

Almost surely, 2^11525721281 is an apocalyptic number.

It is an amenable number.

11525721281 is a deficient number, since it is larger than the sum of its proper divisors (1).

11525721281 is an equidigital number, since it uses as much as digits as its factorization.

11525721281 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11200, while the sum is 35.

The spelling of 11525721281 in words is "eleven billion, five hundred twenty-five million, seven hundred twenty-one thousand, two hundred eighty-one".