18042921 has 12 divisors (see below), whose sum is σ = 28066948. Its totient is φ = 11103264.

The previous prime is 18042917. The next prime is 18042923. The reversal of 18042921 is 12924081.

It can be written as a sum of positive squares in 2 ways, for example, as 3686400 + 14356521 = 1920^2 + 3789^2 .

It is not a de Polignac number, because 18042921 - 2² = 18042917 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18042923) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 76990 + ... + 77223.

Almost surely, 2^18042921 is an apocalyptic number.

It is an amenable number.

18042921 is a deficient number, since it is larger than the sum of its proper divisors (10024027).

18042921 is a wasteful number, since it uses less digits than its factorization.

18042921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 154232 (or 154229 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 27.

The square root of 18042921 is about 4247.6959636961. The cubic root of 18042921 is about 262.2822793337.

The spelling of 18042921 in words is "eighteen million, forty-two thousand, nine hundred twenty-one".