20957197 has 4 divisors (see below), whose sum is σ = 21164796. Its totient is φ = 20749600.

The previous prime is 20957177. The next prime is 20957219. The reversal of 20957197 is 79175902.

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 19766916 + 1190281 = 4446^2 + 1091^2 .

It is a cyclic number.

It is not a de Polignac number, because 20957197 - 2¹⁵ = 20924429 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 (20957177) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 103648 + ... + 103849.

It is an arithmetic number, because the mean of its divisors is an integer number (5291199).

Almost surely, 2^20957197 is an apocalyptic number.

It is an amenable number.

20957197 is a deficient number, since it is larger than the sum of its proper divisors (207599).

20957197 is a wasteful number, since it uses less digits than its factorization.

20957197 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 207598.

The product of its (nonzero) digits is 39690, while the sum is 40.

The square root of 20957197 is about 4577.9031226097. The cubic root of 20957197 is about 275.7048453294.

The spelling of 20957197 in words is "twenty million, nine hundred fifty-seven thousand, one hundred ninety-seven".