21002138 has 16 divisors (see below), whose sum is σ = 32313600. Its totient is φ = 10232976.

The previous prime is 21002129. The next prime is 21002203. The reversal of 21002138 is 83120012.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 34763 + ... + 35361.

It is an arithmetic number, because the mean of its divisors is an integer number (2019600).

Almost surely, 2^21002138 is an apocalyptic number.

21002138 is a deficient number, since it is larger than the sum of its proper divisors (11311462).

21002138 is a wasteful number, since it uses less digits than its factorization.

21002138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1021.

The product of its (nonzero) digits is 96, while the sum is 17.

The square root of 21002138 is about 4582.8089639434. The cubic root of 21002138 is about 275.9017801456.

The spelling of 21002138 in words is "twenty-one million, two thousand, one hundred thirty-eight".