20312157 has 4 divisors (see below), whose sum is σ = 27082880. Its totient is φ = 13541436.

The previous prime is 20312153. The next prime is 20312191. The reversal of 20312157 is 75121302.

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 not a de Polignac number, because 20312157 - 2² = 20312153 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 (20312153) 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, 3385357 + ... + 3385362.

It is an arithmetic number, because the mean of its divisors is an integer number (6770720).

Almost surely, 2^20312157 is an apocalyptic number.

It is an amenable number.

20312157 is a deficient number, since it is larger than the sum of its proper divisors (6770723).

20312157 is an equidigital number, since it uses as much as digits as its factorization.

20312157 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6770722.

The product of its (nonzero) digits is 420, while the sum is 21.

The square root of 20312157 is about 4506.9010417359. The cubic root of 20312157 is about 272.8466849710.

Adding to 20312157 its reverse (75121302), we get a palindrome (95433459).

The spelling of 20312157 in words is "twenty million, three hundred twelve thousand, one hundred fifty-seven".