19938021 has 16 divisors (see below), whose sum is σ = 27048000. Its totient is φ = 13062528.

The previous prime is 19938001. The next prime is 19938029. The reversal of 19938021 is 12083991.

It is not a de Polignac number, because 19938021 - 2⁷ = 19937893 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19938029) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 56955 + ... + 57303.

It is an arithmetic number, because the mean of its divisors is an integer number (1690500).

Almost surely, 2^19938021 is an apocalyptic number.

It is an amenable number.

19938021 is a deficient number, since it is larger than the sum of its proper divisors (7109979).

19938021 is a wasteful number, since it uses less digits than its factorization.

19938021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 628.

The product of its (nonzero) digits is 3888, while the sum is 33.

The square root of 19938021 is about 4465.2011152914. The cubic root of 19938021 is about 271.1610767009.

The spelling of 19938021 in words is "nineteen million, nine hundred thirty-eight thousand, twenty-one".