21469757 has 2 divisors, whose sum is σ = 21469758. Its totient is φ = 21469756.

The previous prime is 21469739. The next prime is 21469783. The reversal of 21469757 is 75796412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12313081 + 9156676 = 3509^2 + 3026^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21469757 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21469057) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10734878 + 10734879.

It is an arithmetic number, because the mean of its divisors is an integer number (10734879).

Almost surely, 2^21469757 is an apocalyptic number.

It is an amenable number.

21469757 is a deficient number, since it is larger than the sum of its proper divisors (1).

21469757 is an equidigital number, since it uses as much as digits as its factorization.

21469757 is an evil number, because the sum of its binary digits is even.

The product of its digits is 105840, while the sum is 41.

The square root of 21469757 is about 4633.5469135426. The cubic root of 21469757 is about 277.9344470456.

The spelling of 21469757 in words is "twenty-one million, four hundred sixty-nine thousand, seven hundred fifty-seven".