21935657 has 2 divisors, whose sum is σ = 21935658. Its totient is φ = 21935656.

The previous prime is 21935653. The next prime is 21935707. The reversal of 21935657 is 75653912.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14295961 + 7639696 = 3781^2 + 2764^2 .

It is a cyclic number.

It is not a de Polignac number, because 21935657 - 2² = 21935653 is a prime.

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 21935657.

It is not a weakly prime, because it can be changed into another prime (21935653) 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, 10967828 + 10967829.

It is an arithmetic number, because the mean of its divisors is an integer number (10967829).

Almost surely, 2^21935657 is an apocalyptic number.

It is an amenable number.

21935657 is a deficient number, since it is larger than the sum of its proper divisors (1).

21935657 is an equidigital number, since it uses as much as digits as its factorization.

21935657 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 56700, while the sum is 38.

The square root of 21935657 is about 4683.5517505415. The cubic root of 21935657 is about 279.9304972049.

The spelling of 21935657 in words is "twenty-one million, nine hundred thirty-five thousand, six hundred fifty-seven".