21966957 has 14 divisors (see below), whose sum is σ = 32936462. Its totient is φ = 14644152.

The previous prime is 21966899. The next prime is 21966961. The reversal of 21966957 is 75966912.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 17065161 + 4901796 = 4131^2 + 2214^2 .

It is a de Polignac number, because none of the positive numbers 2^k-21966957 is a prime.

It is a Duffinian number.

It is a zygodrome in base 11.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21966257) 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 in 13 ways as a sum of consecutive naturals, for example, 14338 + ... + 15795.

Almost surely, 2^21966957 is an apocalyptic number.

21966957 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

It is an amenable number.

21966957 is a deficient number, since it is larger than the sum of its proper divisors (10969505).

21966957 is an frugal number, since it uses more digits than its factorization.

21966957 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30151 (or 30136 counting only the distinct ones).

The product of its digits is 204120, while the sum is 45.

The square root of 21966957 is about 4686.8920405744. The cubic root of 21966957 is about 280.0635782496.

Subtracting from 21966957 its sum of digits (45), we obtain a palindrome (21966912).

It can be divided in two parts, 219 and 66957, that added together give a palindrome (67176).

The spelling of 21966957 in words is "twenty-one million, nine hundred sixty-six thousand, nine hundred fifty-seven".