161515505537 has 2 divisors, whose sum is σ = 161515505538. Its totient is φ = 161515505536.

The previous prime is 161515505527. The next prime is 161515505603. The reversal of 161515505537 is 735505515161.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 123836425216 + 37679080321 = 351904^2 + 194111^2 .

It is a cyclic number.

It is not a de Polignac number, because 161515505537 - 2²⁶ = 161448396673 is a prime.

It is not a weakly prime, because it can be changed into another prime (161515505527) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80757752768 + 80757752769.

It is an arithmetic number, because the mean of its divisors is an integer number (80757752769).

Almost surely, 2^161515505537 is an apocalyptic number.

It is an amenable number.

161515505537 is a deficient number, since it is larger than the sum of its proper divisors (1).

161515505537 is an equidigital number, since it uses as much as digits as its factorization.

161515505537 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 393750, while the sum is 44.

The spelling of 161515505537 in words is "one hundred sixty-one billion, five hundred fifteen million, five hundred five thousand, five hundred thirty-seven".