21973297 has 4 divisors (see below), whose sum is σ = 22251520. Its totient is φ = 21695076.

The previous prime is 21973261. The next prime is 21973307. The reversal of 21973297 is 79237912.

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 21973297 - 2⁷ = 21973169 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21973207) 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, 138993 + ... + 139150.

It is an arithmetic number, because the mean of its divisors is an integer number (5562880).

Almost surely, 2^21973297 is an apocalyptic number.

It is an amenable number.

21973297 is a deficient number, since it is larger than the sum of its proper divisors (278223).

21973297 is an equidigital number, since it uses as much as digits as its factorization.

21973297 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 278222.

The product of its digits is 47628, while the sum is 40.

The square root of 21973297 is about 4687.5683461684. The cubic root of 21973297 is about 280.0905192029.

The spelling of 21973297 in words is "twenty-one million, nine hundred seventy-three thousand, two hundred ninety-seven".