161554517 has 2 divisors, whose sum is σ = 161554518. Its totient is φ = 161554516.

The previous prime is 161554513. The next prime is 161554537. The reversal of 161554517 is 715455161.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 134420836 + 27133681 = 11594^2 + 5209^2 .

It is an emirp because it is prime and its reverse (715455161) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 161554517 - 2² = 161554513 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161554513) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80777258 + 80777259.

It is an arithmetic number, because the mean of its divisors is an integer number (80777259).

Almost surely, 2^161554517 is an apocalyptic number.

It is an amenable number.

161554517 is a deficient number, since it is larger than the sum of its proper divisors (1).

161554517 is an equidigital number, since it uses as much as digits as its factorization.

161554517 is an evil number, because the sum of its binary digits is even.

The product of its digits is 21000, while the sum is 35.

The square root of 161554517 is about 12710.4097888306. The cubic root of 161554517 is about 544.6360300233.

The spelling of 161554517 in words is "one hundred sixty-one million, five hundred fifty-four thousand, five hundred seventeen".