131228720 has 80 divisors (see below), whose sum is σ = 352745280. Its totient is φ = 44470272.

The previous prime is 131228711. The next prime is 131228723. The reversal of 131228720 is 27822131.

It is a tau number, because it is divible by the number of its divisors (80).

It is a self number, because there is not a number n which added to its sum of digits gives 131228720.

It is not an unprimeable number, because it can be changed into a prime (131228723) 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, 48524 + ... + 51156.

It is an arithmetic number, because the mean of its divisors is an integer number (4409316).

Almost surely, 2^131228720 is an apocalyptic number.

131228720 is a gapful number since it is divisible by the number (10) 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 131228720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (176372640).

131228720 is an abundant number, since it is smaller than the sum of its proper divisors (221516560).

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

131228720 is a wasteful number, since it uses less digits than its factorization.

131228720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2742 (or 2736 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 26.

The square root of 131228720 is about 11455.5104644010. The cubic root of 131228720 is about 508.1707116347.

The spelling of 131228720 in words is "one hundred thirty-one million, two hundred twenty-eight thousand, seven hundred twenty".