21966401 has 2 divisors, whose sum is σ = 21966402. Its totient is φ = 21966400.

The previous prime is 21966359. The next prime is 21966463. The reversal of 21966401 is 10466912.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18447025 + 3519376 = 4295^2 + 1876^2 .

It is a cyclic number.

It is not a de Polignac number, because 21966401 - 2¹⁴ = 21950017 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21966481) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10983200 + 10983201.

It is an arithmetic number, because the mean of its divisors is an integer number (10983201).

Almost surely, 2^21966401 is an apocalyptic number.

It is an amenable number.

21966401 is a deficient number, since it is larger than the sum of its proper divisors (1).

21966401 is an equidigital number, since it uses as much as digits as its factorization.

21966401 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2592, while the sum is 29.

The square root of 21966401 is about 4686.8327258395. The cubic root of 21966401 is about 280.0612153572.

The spelling of 21966401 in words is "twenty-one million, nine hundred sixty-six thousand, four hundred one".