15616061521 has 2 divisors, whose sum is σ = 15616061522. Its totient is φ = 15616061520.

The previous prime is 15616061519. The next prime is 15616061537. The reversal of 15616061521 is 12516061651.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15615251521 + 810000 = 124961^2 + 900^2 .

It is a cyclic number.

It is not a de Polignac number, because 15616061521 - 2¹ = 15616061519 is a prime.

It is a super-2 number, since 2×15616061521² (a number of 21 digits) contains 22 as substring.

Together with 15616061519, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (15616061561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7808030760 + 7808030761.

It is an arithmetic number, because the mean of its divisors is an integer number (7808030761).

Almost surely, 2^15616061521 is an apocalyptic number.

It is an amenable number.

15616061521 is a deficient number, since it is larger than the sum of its proper divisors (1).

15616061521 is an equidigital number, since it uses as much as digits as its factorization.

15616061521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10800, while the sum is 34.

The spelling of 15616061521 in words is "fifteen billion, six hundred sixteen million, sixty-one thousand, five hundred twenty-one".