16161511516261 has 2 divisors, whose sum is σ = 16161511516262. Its totient is φ = 16161511516260.

The previous prime is 16161511516259. The next prime is 16161511516277. The reversal of 16161511516261 is 16261511516161.

16161511516261 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14461903900161 + 1699607616100 = 3802881^2 + 1303690^2 .

It is a cyclic number.

It is not a de Polignac number, because 16161511516261 - 2¹ = 16161511516259 is a prime.

It is a super-2 number, since 2×16161511516261² (a number of 27 digits) contains 22 as substring.

Together with 16161511516259, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16161511516231) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8080755758130 + 8080755758131.

It is an arithmetic number, because the mean of its divisors is an integer number (8080755758131).

Almost surely, 2^{16161511516261} is an apocalyptic number.

It is an amenable number.

16161511516261 is a deficient number, since it is larger than the sum of its proper divisors (1).

16161511516261 is an equidigital number, since it uses as much as digits as its factorization.

16161511516261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 64800, while the sum is 43.

The spelling of 16161511516261 in words is "sixteen trillion, one hundred sixty-one billion, five hundred eleven million, five hundred sixteen thousand, two hundred sixty-one".