90724641521 has 2 divisors, whose sum is σ = 90724641522. Its totient is φ = 90724641520.

The previous prime is 90724641481. The next prime is 90724641529. The reversal of 90724641521 is 12514642709.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 72846010000 + 17878631521 = 269900^2 + 133711^2 .

It is a cyclic number.

It is not a de Polignac number, because 90724641521 - 2¹⁸ = 90724379377 is a prime.

It is a super-2 number, since 2×90724641521² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (90724641529) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45362320760 + 45362320761.

It is an arithmetic number, because the mean of its divisors is an integer number (45362320761).

Almost surely, 2^90724641521 is an apocalyptic number.

It is an amenable number.

90724641521 is a deficient number, since it is larger than the sum of its proper divisors (1).

90724641521 is an equidigital number, since it uses as much as digits as its factorization.

90724641521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 120960, while the sum is 41.

The spelling of 90724641521 in words is "ninety billion, seven hundred twenty-four million, six hundred forty-one thousand, five hundred twenty-one".