231817428 has 36 divisors (see below), whose sum is σ = 587064660. Its totient is φ = 77129856.

The previous prime is 231817427. The next prime is 231817441. The reversal of 231817428 is 824718132.

It can be written as a sum of positive squares in 2 ways, for example, as 144432324 + 87385104 = 12018^2 + 9348^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 231817392 and 231817401.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (231817427) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 14826 + ... + 26142.

Almost surely, 2^231817428 is an apocalyptic number.

It is an amenable number.

231817428 is an abundant number, since it is smaller than the sum of its proper divisors (355247232).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

231817428 is a wasteful number, since it uses less digits than its factorization.

231817428 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11896 (or 11891 counting only the distinct ones).

The product of its digits is 21504, while the sum is 36.

The square root of 231817428 is about 15225.5518126602. The cubic root of 231817428 is about 614.3021392090.

The spelling of 231817428 in words is "two hundred thirty-one million, eight hundred seventeen thousand, four hundred twenty-eight".