18699021 has 24 divisors (see below), whose sum is σ = 31019040. Its totient is φ = 10735200.

The previous prime is 18699019. The next prime is 18699041. The reversal of 18699021 is 12099681.

It is not a de Polignac number, because 18699021 - 2¹ = 18699019 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18699041) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3090 + ... + 6851.

It is an arithmetic number, because the mean of its divisors is an integer number (1292460).

Almost surely, 2^18699021 is an apocalyptic number.

18699021 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

18699021 is a deficient number, since it is larger than the sum of its proper divisors (12320019).

18699021 is a wasteful number, since it uses less digits than its factorization.

18699021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9977 (or 9974 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 36.

The square root of 18699021 is about 4324.2364643946. The cubic root of 18699021 is about 265.4236536629.

The spelling of 18699021 in words is "eighteen million, six hundred ninety-nine thousand, twenty-one".