161621171 has 2 divisors, whose sum is σ = 161621172. Its totient is φ = 161621170.

The previous prime is 161621113. The next prime is 161621179. The reversal of 161621171 is 171126161.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 161621171 - 2¹⁸ = 161359027 is a prime.

It is a super-2 number, since 2×161621171² = 52242805830822482, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 161621171.

It is not a weakly prime, because it can be changed into another prime (161621179) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80810585 + 80810586.

It is an arithmetic number, because the mean of its divisors is an integer number (80810586).

Almost surely, 2^161621171 is an apocalyptic number.

161621171 is a deficient number, since it is larger than the sum of its proper divisors (1).

161621171 is an equidigital number, since it uses as much as digits as its factorization.

161621171 is an evil number, because the sum of its binary digits is even.

The product of its digits is 504, while the sum is 26.

The square root of 161621171 is about 12713.0315424764. The cubic root of 161621171 is about 544.7109215197.

The spelling of 161621171 in words is "one hundred sixty-one million, six hundred twenty-one thousand, one hundred seventy-one".