21966497 has 4 divisors (see below), whose sum is σ = 25104576. Its totient is φ = 18828420.

The previous prime is 21966491. The next prime is 21966521. The reversal of 21966497 is 79466912.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21966497 - 2⁴ = 21966481 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21966491) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1569029 + ... + 1569042.

It is an arithmetic number, because the mean of its divisors is an integer number (6276144).

Almost surely, 2^21966497 is an apocalyptic number.

It is an amenable number.

21966497 is a deficient number, since it is larger than the sum of its proper divisors (3138079).

21966497 is an equidigital number, since it uses as much as digits as its factorization.

21966497 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3138078.

The product of its digits is 163296, while the sum is 44.

The square root of 21966497 is about 4686.8429672862. The cubic root of 21966497 is about 280.0616233415.

The spelling of 21966497 in words is "twenty-one million, nine hundred sixty-six thousand, four hundred ninety-seven".