21933557 has 2 divisors, whose sum is σ = 21933558. Its totient is φ = 21933556.

The previous prime is 21933551. The next prime is 21933577. The reversal of 21933557 is 75533912.

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., 21613201 + 320356 = 4649^2 + 566^2 .

It is a cyclic number.

It is not a de Polignac number, because 21933557 - 2¹² = 21929461 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21933551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10966778 + 10966779.

It is an arithmetic number, because the mean of its divisors is an integer number (10966779).

Almost surely, 2^21933557 is an apocalyptic number.

It is an amenable number.

21933557 is a deficient number, since it is larger than the sum of its proper divisors (1).

21933557 is an equidigital number, since it uses as much as digits as its factorization.

21933557 is an evil number, because the sum of its binary digits is even.

The product of its digits is 28350, while the sum is 35.

The square root of 21933557 is about 4683.3275563428. The cubic root of 21933557 is about 279.9215639142.

The spelling of 21933557 in words is "twenty-one million, nine hundred thirty-three thousand, five hundred fifty-seven".