21970771 has 2 divisors, whose sum is σ = 21970772. Its totient is φ = 21970770.

The previous prime is 21970763. The next prime is 21970811. The reversal of 21970771 is 17707912.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21970771 - 2³ = 21970763 is a prime.

It is not a weakly prime, because it can be changed into another prime (21970271) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10985385 + 10985386.

It is an arithmetic number, because the mean of its divisors is an integer number (10985386).

Almost surely, 2^21970771 is an apocalyptic number.

21970771 is a deficient number, since it is larger than the sum of its proper divisors (1).

21970771 is an equidigital number, since it uses as much as digits as its factorization.

21970771 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6174, while the sum is 34.

The square root of 21970771 is about 4687.2989023530. The cubic root of 21970771 is about 280.0797859363.

The spelling of 21970771 in words is "twenty-one million, nine hundred seventy thousand, seven hundred seventy-one".