21702997 has 4 divisors (see below), whose sum is σ = 22845280. Its totient is φ = 20560716.

The previous prime is 21702983. The next prime is 21703009. The reversal of 21702997 is 79920712.

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 21702997 - 2¹¹ = 21700949 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21702907) 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, 571113 + ... + 571150.

It is an arithmetic number, because the mean of its divisors is an integer number (5711320).

Almost surely, 2^21702997 is an apocalyptic number.

It is an amenable number.

21702997 is a deficient number, since it is larger than the sum of its proper divisors (1142283).

21702997 is a wasteful number, since it uses less digits than its factorization.

21702997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1142282.

The product of its (nonzero) digits is 15876, while the sum is 37.

The square root of 21702997 is about 4658.6475505236. The cubic root of 21702997 is about 278.9372854418.

The spelling of 21702997 in words is "twenty-one million, seven hundred two thousand, nine hundred ninety-seven".