20397231 has 16 divisors (see below), whose sum is σ = 30424320. Its totient is φ = 13505400.

The previous prime is 20397227. The next prime is 20397233. The reversal of 20397231 is 13279302.

It is not a de Polignac number, because 20397231 - 2² = 20397227 is a prime.

It is a super-2 number, since 2×20397231² = 832094064934722, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a junction number, because it is equal to n+sod(n) for n = 20397195 and 20397204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20397233) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1576 + ... + 6578.

It is an arithmetic number, because the mean of its divisors is an integer number (1901520).

Almost surely, 2^20397231 is an apocalyptic number.

20397231 is a deficient number, since it is larger than the sum of its proper divisors (10027089).

20397231 is a wasteful number, since it uses less digits than its factorization.

20397231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5163 (or 5157 counting only the distinct ones).

The product of its (nonzero) digits is 2268, while the sum is 27.

The square root of 20397231 is about 4516.3293723997. The cubic root of 20397231 is about 273.2270783047.

The spelling of 20397231 in words is "twenty million, three hundred ninety-seven thousand, two hundred thirty-one".