21660963 has 12 divisors (see below), whose sum is σ = 30193800. Its totient is φ = 13811776.

The previous prime is 21660959. The next prime is 21660967. The reversal of 21660963 is 36906612.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21660959) and next prime (21660967).

It is not a de Polignac number, because 21660963 - 2² = 21660959 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21660967) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5238 + ... + 8411.

It is an arithmetic number, because the mean of its divisors is an integer number (2516150).

Almost surely, 2^21660963 is an apocalyptic number.

21660963 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

21660963 is a deficient number, since it is larger than the sum of its proper divisors (8532837).

21660963 is a wasteful number, since it uses less digits than its factorization.

21660963 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13698 (or 13675 counting only the distinct ones).

The product of its (nonzero) digits is 11664, while the sum is 33.

The square root of 21660963 is about 4654.1339688496. The cubic root of 21660963 is about 278.7570887082.

The spelling of 21660963 in words is "twenty-one million, six hundred sixty thousand, nine hundred sixty-three".