21469739 has 2 divisors, whose sum is σ = 21469740. Its totient is φ = 21469738.

The previous prime is 21469733. The next prime is 21469757. The reversal of 21469739 is 93796412.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21469739 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21469696 and 21469705.

It is not a weakly prime, because it can be changed into another prime (21469733) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10734869 + 10734870.

It is an arithmetic number, because the mean of its divisors is an integer number (10734870).

Almost surely, 2^21469739 is an apocalyptic number.

21469739 is a deficient number, since it is larger than the sum of its proper divisors (1).

21469739 is an equidigital number, since it uses as much as digits as its factorization.

21469739 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 81648, while the sum is 41.

The square root of 21469739 is about 4633.5449711857. The cubic root of 21469739 is about 277.9343693733.

The spelling of 21469739 in words is "twenty-one million, four hundred sixty-nine thousand, seven hundred thirty-nine".