21965731 has 8 divisors (see below), whose sum is σ = 22927680. Its totient is φ = 21017472.

The previous prime is 21965719. The next prime is 21965737. The reversal of 21965731 is 13756912.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21965731 - 2⁹ = 21965219 is a prime.

It is a super-2 number, since 2×21965731² = 964986676728722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21965737) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 75 + ... + 6628.

It is an arithmetic number, because the mean of its divisors is an integer number (2865960).

Almost surely, 2^21965731 is an apocalyptic number.

21965731 is a deficient number, since it is larger than the sum of its proper divisors (961949).

21965731 is a wasteful number, since it uses less digits than its factorization.

21965731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6845.

The product of its digits is 11340, while the sum is 34.

The square root of 21965731 is about 4686.7612484529. The cubic root of 21965731 is about 280.0583679340.

The spelling of 21965731 in words is "twenty-one million, nine hundred sixty-five thousand, seven hundred thirty-one".