18208957 has 4 divisors (see below), whose sum is σ = 19609660. Its totient is φ = 16808256.

The previous prime is 18208951. The next prime is 18208963. The reversal of 18208957 is 75980281.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 75980281 = 13 ⋅5844637.

It is an interprime number because it is at equal distance from previous prime (18208951) and next prime (18208963).

It can be written as a sum of positive squares in 2 ways, for example, as 3006756 + 15202201 = 1734^2 + 3899^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18208957 is a prime.

It is a super-2 number, since 2×18208957² = 663132230055698, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18208951) 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, 700332 + ... + 700357.

It is an arithmetic number, because the mean of its divisors is an integer number (4902415).

Almost surely, 2^18208957 is an apocalyptic number.

It is an amenable number.

18208957 is a deficient number, since it is larger than the sum of its proper divisors (1400703).

18208957 is a wasteful number, since it uses less digits than its factorization.

18208957 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1400702.

The product of its (nonzero) digits is 40320, while the sum is 40.

The square root of 18208957 is about 4267.1954490039. The cubic root of 18208957 is about 263.0843556361.

The spelling of 18208957 in words is "eighteen million, two hundred eight thousand, nine hundred fifty-seven".