231661136420 has 96 divisors (see below), whose sum is σ = 569820545280. Its totient is φ = 77452277760.

The previous prime is 231661136419. The next prime is 231661136437. The reversal of 231661136420 is 24631166132.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 13635491 + ... + 13652469.

It is an arithmetic number, because the mean of its divisors is an integer number (5935630680).

Almost surely, 2^231661136420 is an apocalyptic number.

231661136420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 231661136420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (284910272640).

231661136420 is an abundant number, since it is smaller than the sum of its proper divisors (338159408860).

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

231661136420 is a wasteful number, since it uses less digits than its factorization.

231661136420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19413 (or 19411 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 35.

The spelling of 231661136420 in words is "two hundred thirty-one billion, six hundred sixty-one million, one hundred thirty-six thousand, four hundred twenty".