20257231 has 4 divisors (see below), whose sum is σ = 20405232. Its totient is φ = 20109232.

The previous prime is 20257219. The next prime is 20257247. The reversal of 20257231 is 13275202.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13275202 = 2 ⋅6637601.

It is a cyclic number.

It is not a de Polignac number, because 20257231 - 2¹⁷ = 20126159 is a prime.

It is a super-2 number, since 2×20257231² = 820710815574722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20257261) 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, 73795 + ... + 74068.

It is an arithmetic number, because the mean of its divisors is an integer number (5101308).

Almost surely, 2^20257231 is an apocalyptic number.

20257231 is a deficient number, since it is larger than the sum of its proper divisors (148001).

20257231 is a wasteful number, since it uses less digits than its factorization.

20257231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 148000.

The product of its (nonzero) digits is 840, while the sum is 22.

The square root of 20257231 is about 4500.8033727325. The cubic root of 20257231 is about 272.6005285182.

The spelling of 20257231 in words is "twenty million, two hundred fifty-seven thousand, two hundred thirty-one".