21131039 has 2 divisors, whose sum is σ = 21131040. Its totient is φ = 21131038.

The previous prime is 21131029. The next prime is 21131041. The reversal of 21131039 is 93013112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21131039 - 2⁸ = 21130783 is a prime.

Together with 21131041, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21131039.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21131009) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10565519 + 10565520.

It is an arithmetic number, because the mean of its divisors is an integer number (10565520).

Almost surely, 2^21131039 is an apocalyptic number.

21131039 is a deficient number, since it is larger than the sum of its proper divisors (1).

21131039 is an equidigital number, since it uses as much as digits as its factorization.

21131039 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 162, while the sum is 20.

The square root of 21131039 is about 4596.8509873608. The cubic root of 21131039 is about 276.4650800055.

It can be divided in two parts, 2113103 and 9, that added together give a palindrome (2113112).

The spelling of 21131039 in words is "twenty-one million, one hundred thirty-one thousand, thirty-nine".