21913739 has 2 divisors, whose sum is σ = 21913740. Its totient is φ = 21913738.

The previous prime is 21913729. The next prime is 21913741. The reversal of 21913739 is 93731912.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21913739 - 2⁸ = 21913483 is a prime.

Together with 21913741, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21913699 and 21913708.

It is not a weakly prime, because it can be changed into another prime (21913709) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10956869 + 10956870.

It is an arithmetic number, because the mean of its divisors is an integer number (10956870).

Almost surely, 2^21913739 is an apocalyptic number.

21913739 is a deficient number, since it is larger than the sum of its proper divisors (1).

21913739 is an equidigital number, since it uses as much as digits as its factorization.

21913739 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10206, while the sum is 35.

The square root of 21913739 is about 4681.2112748732. The cubic root of 21913739 is about 279.8372310782.

The spelling of 21913739 in words is "twenty-one million, nine hundred thirteen thousand, seven hundred thirty-nine".