1231157 has 4 divisors (see below), whose sum is σ = 1303596. Its totient is φ = 1158720.

The previous prime is 1231141. The next prime is 1231171. The reversal of 1231157 is 7511321.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7511321 = 449 ⋅16729.

It can be written as a sum of positive squares in 2 ways, for example, as 872356 + 358801 = 934^2 + 599^2 .

It is not a de Polignac number, because 1231157 - 2⁴ = 1231141 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 (1231127) 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, 36194 + ... + 36227.

It is an arithmetic number, because the mean of its divisors is an integer number (325899).

2^1231157 is an apocalyptic number.

1231157 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

1231157 is a deficient number, since it is larger than the sum of its proper divisors (72439).

1231157 is an equidigital number, since it uses as much as digits as its factorization.

1231157 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72438.

The product of its digits is 210, while the sum is 20.

The square root of 1231157 is about 1109.5751439177. The cubic root of 1231157 is about 107.1777114964.

Adding to 1231157 its reverse (7511321), we get a palindrome (8742478).

It can be divided in two parts, 123 and 1157, that multiplied together give a triangular number (142311 = T₅₃₃).

The spelling of 1231157 in words is "one million, two hundred thirty-one thousand, one hundred fifty-seven".