20197157 has 4 divisors (see below), whose sum is σ = 20481696. Its totient is φ = 19912620.

The previous prime is 20197141. The next prime is 20197159. The reversal of 20197157 is 75179102.

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, and also an emirpimes, since its reverse is a distinct semiprime: 75179102 = 2 ⋅37589551.

It is a cyclic number.

It is not a de Polignac number, because 20197157 - 2⁴ = 20197141 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 (20197159) 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, 142163 + ... + 142304.

It is an arithmetic number, because the mean of its divisors is an integer number (5120424).

Almost surely, 2^20197157 is an apocalyptic number.

It is an amenable number.

20197157 is a deficient number, since it is larger than the sum of its proper divisors (284539).

20197157 is an equidigital number, since it uses as much as digits as its factorization.

20197157 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 284538.

The product of its (nonzero) digits is 4410, while the sum is 32.

The square root of 20197157 is about 4494.1247201207. The cubic root of 20197157 is about 272.3307907791.

The spelling of 20197157 in words is "twenty million, one hundred ninety-seven thousand, one hundred fifty-seven".