16623557 has 4 divisors (see below), whose sum is σ = 16636620. Its totient is φ = 16610496.

The previous prime is 16623553. The next prime is 16623559. The reversal of 16623557 is 75532661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 75532661 = 227 ⋅332743.

It can be written as a sum of positive squares in 2 ways, for example, as 5541316 + 11082241 = 2354^2 + 3329^2 .

It is a cyclic number.

It is not a de Polignac number, because 16623557 - 2² = 16623553 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16623553) 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, 4388 + ... + 7245.

It is an arithmetic number, because the mean of its divisors is an integer number (4159155).

Almost surely, 2^16623557 is an apocalyptic number.

It is an amenable number.

16623557 is a deficient number, since it is larger than the sum of its proper divisors (13063).

16623557 is a wasteful number, since it uses less digits than its factorization.

16623557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13062.

The product of its digits is 37800, while the sum is 35.

The square root of 16623557 is about 4077.1996517218. The cubic root of 16623557 is about 255.2160516775.

The spelling of 16623557 in words is "sixteen million, six hundred twenty-three thousand, five hundred fifty-seven".