161663251 has 8 divisors (see below), whose sum is σ = 178615584. Its totient is φ = 145537920.

The previous prime is 161663239. The next prime is 161663261. The reversal of 161663251 is 152366161.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 161663251 - 2⁵ = 161663219 is a prime.

It is a super-2 number, since 2×161663251² = 52270013447778002, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161663261) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 206340 + ... + 207121.

It is an arithmetic number, because the mean of its divisors is an integer number (22326948).

Almost surely, 2^161663251 is an apocalyptic number.

161663251 is a deficient number, since it is larger than the sum of its proper divisors (16952333).

161663251 is a wasteful number, since it uses less digits than its factorization.

161663251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 413501.

The product of its digits is 6480, while the sum is 31.

The square root of 161663251 is about 12714.6864294799. The cubic root of 161663251 is about 544.7581914131.

The spelling of 161663251 in words is "one hundred sixty-one million, six hundred sixty-three thousand, two hundred fifty-one".