161621516 has 36 divisors (see below), whose sum is σ = 343393008. Its totient is φ = 65188608.

The previous prime is 161621459. The next prime is 161621531. The reversal of 161621516 is 615126161.

It is a super-2 number, since 2×161621516² = 52243028868276512, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1895 + ... + 18078.

Almost surely, 2^161621516 is an apocalyptic number.

It is an amenable number.

161621516 is an abundant number, since it is smaller than the sum of its proper divisors (181771492).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

161621516 is a wasteful number, since it uses less digits than its factorization.

161621516 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20018 (or 19999 counting only the distinct ones).

The product of its digits is 2160, while the sum is 29.

The square root of 161621516 is about 12713.0451112234. The cubic root of 161621516 is about 544.7113091033.

Adding to 161621516 its reverse (615126161), we get a palindrome (776747677).

It can be divided in two parts, 1616 and 21516, that added together give a palindrome (23132).

The spelling of 161621516 in words is "one hundred sixty-one million, six hundred twenty-one thousand, five hundred sixteen".