18742491 has 6 divisors (see below), whose sum is σ = 27072500. Its totient is φ = 12494988.

The previous prime is 18742487. The next prime is 18742501. The reversal of 18742491 is 19424781.

It is not a de Polignac number, because 18742491 - 2² = 18742487 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18742391) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1041241 + ... + 1041258.

Almost surely, 2^18742491 is an apocalyptic number.

18742491 is a deficient number, since it is larger than the sum of its proper divisors (8330009).

18742491 is a wasteful number, since it uses less digits than its factorization.

18742491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2082505 (or 2082502 counting only the distinct ones).

The product of its digits is 16128, while the sum is 36.

The square root of 18742491 is about 4329.2598674600. The cubic root of 18742491 is about 265.6291731017.

The spelling of 18742491 in words is "eighteen million, seven hundred forty-two thousand, four hundred ninety-one".