21572197 has 8 divisors (see below), whose sum is σ = 22193600. Its totient is φ = 20956320.

The previous prime is 21572179. The next prime is 21572209. The reversal of 21572197 is 79127512.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21572197 - 2⁷ = 21572069 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 (21572297) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7297 + ... + 9817.

It is an arithmetic number, because the mean of its divisors is an integer number (2774200).

Almost surely, 2^21572197 is an apocalyptic number.

It is an amenable number.

21572197 is a deficient number, since it is larger than the sum of its proper divisors (621403).

21572197 is a wasteful number, since it uses less digits than its factorization.

21572197 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2763.

The product of its digits is 8820, while the sum is 34.

The square root of 21572197 is about 4644.5879257476. The cubic root of 21572197 is about 278.3757878834.

The spelling of 21572197 in words is "twenty-one million, five hundred seventy-two thousand, one hundred ninety-seven".