21982297 has 4 divisors (see below), whose sum is σ = 23139280. Its totient is φ = 20825316.

The previous prime is 21982277. The next prime is 21982313. The reversal of 21982297 is 79228912.

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 21982297 - 2¹⁹ = 21458009 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21982217) 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, 578463 + ... + 578500.

It is an arithmetic number, because the mean of its divisors is an integer number (5784820).

Almost surely, 2^21982297 is an apocalyptic number.

It is an amenable number.

21982297 is a deficient number, since it is larger than the sum of its proper divisors (1156983).

21982297 is a wasteful number, since it uses less digits than its factorization.

21982297 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1156982.

The product of its digits is 36288, while the sum is 40.

The square root of 21982297 is about 4688.5282338917. The cubic root of 21982297 is about 280.1287545602.

The spelling of 21982297 in words is "twenty-one million, nine hundred eighty-two thousand, two hundred ninety-seven".