21022357 has 2 divisors, whose sum is σ = 21022358. Its totient is φ = 21022356.

The previous prime is 21022279. The next prime is 21022363. The reversal of 21022357 is 75322012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16966161 + 4056196 = 4119^2 + 2014^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21022357 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21022367) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10511178 + 10511179.

It is an arithmetic number, because the mean of its divisors is an integer number (10511179).

Almost surely, 2^21022357 is an apocalyptic number.

It is an amenable number.

21022357 is a deficient number, since it is larger than the sum of its proper divisors (1).

21022357 is an equidigital number, since it uses as much as digits as its factorization.

21022357 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 840, while the sum is 22.

The square root of 21022357 is about 4585.0143947429. The cubic root of 21022357 is about 275.9902896885.

Adding to 21022357 its reverse (75322012), we get a palindrome (96344369).

The spelling of 21022357 in words is "twenty-one million, twenty-two thousand, three hundred fifty-seven".