21139047 has 12 divisors (see below), whose sum is σ = 31862064. Its totient is φ = 13479840.

The previous prime is 21139033. The next prime is 21139061. The reversal of 21139047 is 74093112.

It is an interprime number because it is at equal distance from previous prime (21139033) and next prime (21139061).

It is not a de Polignac number, because 21139047 - 2⁴ = 21139031 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21139047.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21139087) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 50854 + ... + 51267.

It is an arithmetic number, because the mean of its divisors is an integer number (2655172).

Almost surely, 2^21139047 is an apocalyptic number.

21139047 is a deficient number, since it is larger than the sum of its proper divisors (10723017).

21139047 is a wasteful number, since it uses less digits than its factorization.

21139047 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 102150 (or 102147 counting only the distinct ones).

The product of its (nonzero) digits is 1512, while the sum is 27.

The square root of 21139047 is about 4597.7219359157. The cubic root of 21139047 is about 276.4999994550.

The spelling of 21139047 in words is "twenty-one million, one hundred thirty-nine thousand, forty-seven".