21966971 has 4 divisors (see below), whose sum is σ = 23656752. Its totient is φ = 20277192.

The previous prime is 21966961. The next prime is 21967019. The reversal of 21966971 is 17966912.

It is a semiprime because it is the product of two primes.

It is a de Polignac number, because none of the positive numbers 2^k-21966971 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21966961) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 844871 + ... + 844896.

It is an arithmetic number, because the mean of its divisors is an integer number (5914188).

Almost surely, 2^21966971 is an apocalyptic number.

21966971 is a deficient number, since it is larger than the sum of its proper divisors (1689781).

21966971 is a wasteful number, since it uses less digits than its factorization.

21966971 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1689780.

The product of its digits is 40824, while the sum is 41.

The square root of 21966971 is about 4686.8935341012. The cubic root of 21966971 is about 280.0636377464.

The spelling of 21966971 in words is "twenty-one million, nine hundred sixty-six thousand, nine hundred seventy-one".