161621552 has 40 divisors (see below), whose sum is σ = 327836160. Its totient is φ = 77042240.

The previous prime is 161621531. The next prime is 161621561. The reversal of 161621552 is 255126161.

It is a happy number.

It is a super-2 number, since 2×161621552² = 52243052141777408, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 158099 + ... + 159117.

It is an arithmetic number, because the mean of its divisors is an integer number (8195904).

Almost surely, 2^161621552 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 161621552, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (163918080).

161621552 is an abundant number, since it is smaller than the sum of its proper divisors (166214608).

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

161621552 is a wasteful number, since it uses less digits than its factorization.

161621552 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1481 (or 1475 counting only the distinct ones).

The product of its digits is 3600, while the sum is 29.

The square root of 161621552 is about 12713.0465270918. The cubic root of 161621552 is about 544.7113495467.

The spelling of 161621552 in words is "one hundred sixty-one million, six hundred twenty-one thousand, five hundred fifty-two".