21957337 has 2 divisors, whose sum is σ = 21957338. Its totient is φ = 21957336.

The previous prime is 21957329. The next prime is 21957343. The reversal of 21957337 is 73375912.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15280281 + 6677056 = 3909^2 + 2584^2 .

It is a cyclic number.

It is not a de Polignac number, because 21957337 - 2³ = 21957329 is a prime.

It is equal to p_1386748 and since 21957337 and 1386748 have the same sum of digits, it is a Honaker prime.

It is a junction number, because it is equal to n+sod(n) for n = 21957296 and 21957305.

It is not a weakly prime, because it can be changed into another prime (21957367) 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, 10978668 + 10978669.

It is an arithmetic number, because the mean of its divisors is an integer number (10978669).

Almost surely, 2^21957337 is an apocalyptic number.

It is an amenable number.

21957337 is a deficient number, since it is larger than the sum of its proper divisors (1).

21957337 is an equidigital number, since it uses as much as digits as its factorization.

21957337 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 39690, while the sum is 37.

The square root of 21957337 is about 4685.8656617534. The cubic root of 21957337 is about 280.0226894879.

The spelling of 21957337 in words is "twenty-one million, nine hundred fifty-seven thousand, three hundred thirty-seven".