18661625 has 16 divisors (see below), whose sum is σ = 24306048. Its totient is φ = 14278000.

The previous prime is 18661607. The next prime is 18661633. The reversal of 18661625 is 52616681.

It is a happy number.

It is not a de Polignac number, because 18661625 - 2⁶ = 18661561 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 371 + ... + 6120.

It is an arithmetic number, because the mean of its divisors is an integer number (1519128).

Almost surely, 2^18661625 is an apocalyptic number.

It is an amenable number.

18661625 is a deficient number, since it is larger than the sum of its proper divisors (5644423).

18661625 is an equidigital number, since it uses as much as digits as its factorization.

18661625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6529 (or 6519 counting only the distinct ones).

The product of its digits is 17280, while the sum is 35.

The square root of 18661625 is about 4319.9102999947. The cubic root of 18661625 is about 265.2465961378.

The spelling of 18661625 in words is "eighteen million, six hundred sixty-one thousand, six hundred twenty-five".