16625621 has 4 divisors (see below), whose sum is σ = 16679052. Its totient is φ = 16572192.

The previous prime is 16625597. The next prime is 16625663. The reversal of 16625621 is 12652661.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7102225 + 9523396 = 2665^2 + 3086^2 .

It is a cyclic number.

It is not a de Polignac number, because 16625621 - 2²² = 12431317 is a prime.

It is a super-2 number, since 2×16625621² = 552822547271282, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16625681) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26246 + ... + 26871.

It is an arithmetic number, because the mean of its divisors is an integer number (4169763).

Almost surely, 2^16625621 is an apocalyptic number.

It is an amenable number.

16625621 is a deficient number, since it is larger than the sum of its proper divisors (53431).

16625621 is an equidigital number, since it uses as much as digits as its factorization.

16625621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53430.

The product of its digits is 4320, while the sum is 29.

The square root of 16625621 is about 4077.4527587699. The cubic root of 16625621 is about 255.2266138801.

The spelling of 16625621 in words is "sixteen million, six hundred twenty-five thousand, six hundred twenty-one".