21973097 has 4 divisors (see below), whose sum is σ = 22730820. Its totient is φ = 21215376.

The previous prime is 21973069. The next prime is 21973099. The reversal of 21973097 is 79037912.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 3474496 + 18498601 = 1864^2 + 4301^2 .

It is a cyclic number.

It is not a de Polignac number, because 21973097 - 2⁶ = 21973033 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21973097.

It is not an unprimeable number, because it can be changed into a prime (21973099) 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, 378818 + ... + 378875.

It is an arithmetic number, because the mean of its divisors is an integer number (5682705).

Almost surely, 2^21973097 is an apocalyptic number.

It is an amenable number.

21973097 is a deficient number, since it is larger than the sum of its proper divisors (757723).

21973097 is an equidigital number, since it uses as much as digits as its factorization.

21973097 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 757722.

The product of its (nonzero) digits is 23814, while the sum is 38.

The square root of 21973097 is about 4687.5470130976. The cubic root of 21973097 is about 280.0896694097.

The spelling of 21973097 in words is "twenty-one million, nine hundred seventy-three thousand, ninety-seven".