15915087301721 has 2 divisors, whose sum is σ = 15915087301722. Its totient is φ = 15915087301720.

The previous prime is 15915087301661. The next prime is 15915087301723. The reversal of 15915087301721 is 12710378051951.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15907494096400 + 7593205321 = 3988420^2 + 87139^2 .

It is a cyclic number.

It is not a de Polignac number, because 15915087301721 - 2²⁶ = 15915020192857 is a prime.

Together with 15915087301723, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 15915087301721.

It is not a weakly prime, because it can be changed into another prime (15915087301723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7957543650860 + 7957543650861.

It is an arithmetic number, because the mean of its divisors is an integer number (7957543650861).

Almost surely, 2^{15915087301721} is an apocalyptic number.

It is an amenable number.

15915087301721 is a deficient number, since it is larger than the sum of its proper divisors (1).

15915087301721 is an equidigital number, since it uses as much as digits as its factorization.

15915087301721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 529200, while the sum is 50.

The spelling of 15915087301721 in words is "fifteen trillion, nine hundred fifteen billion, eighty-seven million, three hundred one thousand, seven hundred twenty-one".