8161621 has 16 divisors (see below), whose sum is σ = 9354240. Its totient is φ = 7058880.

The previous prime is 8161607. The next prime is 8161627. The reversal of 8161621 is 1261618.

It is not a de Polignac number, because 8161621 - 2⁵ = 8161589 is a prime.

It is a super-2 number, since 2×8161621² = 133224114695282, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8161627) 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, 42636 + ... + 42826.

It is an arithmetic number, because the mean of its divisors is an integer number (584640).

Almost surely, 2^8161621 is an apocalyptic number.

It is an amenable number.

8161621 is a deficient number, since it is larger than the sum of its proper divisors (1192619).

8161621 is a wasteful number, since it uses less digits than its factorization.

8161621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 396.

The product of its digits is 576, while the sum is 25.

The square root of 8161621 is about 2856.8550890796. The cubic root of 8161621 is about 201.3378722010.

The spelling of 8161621 in words is "eight million, one hundred sixty-one thousand, six hundred twenty-one".