21929357 has 2 divisors, whose sum is σ = 21929358. Its totient is φ = 21929356.

The previous prime is 21929339. The next prime is 21929377. The reversal of 21929357 is 75392912.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12013156 + 9916201 = 3466^2 + 3149^2 .

It is a cyclic number.

It is not a de Polignac number, because 21929357 - 2⁶ = 21929293 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 21929357.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21929377) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10964678 + 10964679.

It is an arithmetic number, because the mean of its divisors is an integer number (10964679).

Almost surely, 2^21929357 is an apocalyptic number.

It is an amenable number.

21929357 is a deficient number, since it is larger than the sum of its proper divisors (1).

21929357 is an equidigital number, since it uses as much as digits as its factorization.

21929357 is an evil number, because the sum of its binary digits is even.

The product of its digits is 34020, while the sum is 38.

The square root of 21929357 is about 4682.8791357454. The cubic root of 21929357 is about 279.9036956220.

The spelling of 21929357 in words is "twenty-one million, nine hundred twenty-nine thousand, three hundred fifty-seven".