18742561 has 4 divisors (see below), whose sum is σ = 18868500. Its totient is φ = 18616624.

The previous prime is 18742547. The next prime is 18742571. The reversal of 18742561 is 16524781.

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 5089536 + 13653025 = 2256^2 + 3695^2 .

It is a cyclic number.

It is not a de Polignac number, because 18742561 - 2²³ = 10353953 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18742501) 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, 62746 + ... + 63043.

It is an arithmetic number, because the mean of its divisors is an integer number (4717125).

Almost surely, 2^18742561 is an apocalyptic number.

It is an amenable number.

18742561 is a deficient number, since it is larger than the sum of its proper divisors (125939).

18742561 is a wasteful number, since it uses less digits than its factorization.

18742561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 125938.

The product of its digits is 13440, while the sum is 34.

The square root of 18742561 is about 4329.2679519753. The cubic root of 18742561 is about 265.6295037945.

The spelling of 18742561 in words is "eighteen million, seven hundred forty-two thousand, five hundred sixty-one".