161567990251 has 2 divisors, whose sum is σ = 161567990252. Its totient is φ = 161567990250.

The previous prime is 161567990201. The next prime is 161567990257. The reversal of 161567990251 is 152099765161.

It is a strong prime.

It is an emirp because it is prime and its reverse (152099765161) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 161567990251 - 2²⁹ = 161031119339 is a prime.

It is a super-2 number, since 2×161567990251² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (161567990257) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80783995125 + 80783995126.

It is an arithmetic number, because the mean of its divisors is an integer number (80783995126).

Almost surely, 2^161567990251 is an apocalyptic number.

161567990251 is a deficient number, since it is larger than the sum of its proper divisors (1).

161567990251 is an equidigital number, since it uses as much as digits as its factorization.

161567990251 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1020600, while the sum is 52.

The spelling of 161567990251 in words is "one hundred sixty-one billion, five hundred sixty-seven million, nine hundred ninety thousand, two hundred fifty-one".