20145231 has 6 divisors (see below), whose sum is σ = 29098680. Its totient is φ = 13430148.

The previous prime is 20145193. The next prime is 20145233. The reversal of 20145231 is 13254102.

It is a de Polignac number, because none of the positive numbers 2^k-20145231 is a prime.

It is a super-2 number, since 2×20145231² = 811660664086722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20145233) 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 5 ways as a sum of consecutive naturals, for example, 1119171 + ... + 1119188.

It is an arithmetic number, because the mean of its divisors is an integer number (4849780).

Almost surely, 2^20145231 is an apocalyptic number.

20145231 is a deficient number, since it is larger than the sum of its proper divisors (8953449).

20145231 is a wasteful number, since it uses less digits than its factorization.

20145231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2238365 (or 2238362 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 20145231 is about 4488.3439039361. The cubic root of 20145231 is about 272.0972070021.

Adding to 20145231 its reverse (13254102), we get a palindrome (33399333).

The spelling of 20145231 in words is "twenty million, one hundred forty-five thousand, two hundred thirty-one".