161631625 has 16 divisors (see below), whose sum is σ = 206414208. Its totient is φ = 126294000.

The previous prime is 161631623. The next prime is 161631653. The reversal of 161631625 is 526136161.

It is not a de Polignac number, because 161631625 - 2¹ = 161631623 is a prime.

It is a super-2 number, since 2×161631625² = 52249564400281250, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161631623) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9661 + ... + 20410.

It is an arithmetic number, because the mean of its divisors is an integer number (12900888).

Almost surely, 2^161631625 is an apocalyptic number.

It is an amenable number.

161631625 is a deficient number, since it is larger than the sum of its proper divisors (44782583).

161631625 is an equidigital number, since it uses as much as digits as its factorization.

161631625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30129 (or 30119 counting only the distinct ones).

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

The square root of 161631625 is about 12713.4426887449. The cubic root of 161631625 is about 544.7226656189.

Adding to 161631625 its reverse (526136161), we get a palindrome (687767786).

The spelling of 161631625 in words is "one hundred sixty-one million, six hundred thirty-one thousand, six hundred twenty-five".