18875021 has 4 divisors (see below), whose sum is σ = 20590944. Its totient is φ = 17159100.

The previous prime is 18874997. The next prime is 18875041. The reversal of 18875021 is 12057881.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 18875021 - 2⁶ = 18874957 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18875041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 857945 + ... + 857966.

It is an arithmetic number, because the mean of its divisors is an integer number (5147736).

Almost surely, 2^18875021 is an apocalyptic number.

18875021 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

18875021 is a deficient number, since it is larger than the sum of its proper divisors (1715923).

18875021 is a wasteful number, since it uses less digits than its factorization.

18875021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1715922.

The product of its (nonzero) digits is 4480, while the sum is 32.

The square root of 18875021 is about 4344.5392160734. The cubic root of 18875021 is about 266.2537998238.

The spelling of 18875021 in words is "eighteen million, eight hundred seventy-five thousand, twenty-one".