21139641 has 24 divisors (see below), whose sum is σ = 31842720. Its totient is φ = 13502400.

The previous prime is 21139627. The next prime is 21139649. The reversal of 21139641 is 14693112.

21139641 is a `hidden beast` number, since 2 + 1 + 13 + 9 + 641 = 666.

It is not a de Polignac number, because 21139641 - 2⁶ = 21139577 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21139649) 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, 21286 + ... + 22256.

It is an arithmetic number, because the mean of its divisors is an integer number (1326780).

Almost surely, 2^21139641 is an apocalyptic number.

It is an amenable number.

21139641 is a deficient number, since it is larger than the sum of its proper divisors (10703079).

21139641 is a wasteful number, since it uses less digits than its factorization.

21139641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1077 (or 1074 counting only the distinct ones).

The product of its digits is 1296, while the sum is 27.

The square root of 21139641 is about 4597.7865326698. The cubic root of 21139641 is about 276.5025892826.

The spelling of 21139641 in words is "twenty-one million, one hundred thirty-nine thousand, six hundred forty-one".