131405220 has 48 divisors (see below), whose sum is σ = 408817920. Its totient is φ = 35041248.

The previous prime is 131405201. The next prime is 131405227. The reversal of 131405220 is 22504131.

131405220 is a `hidden beast` number, since 1 + 3 + 140 + 522 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 131405193 and 131405202.

It is not an unprimeable number, because it can be changed into a prime (131405227) 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, 121132 + ... + 122211.

It is an arithmetic number, because the mean of its divisors is an integer number (8517040).

Almost surely, 2^131405220 is an apocalyptic number.

131405220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

131405220 is an abundant number, since it is smaller than the sum of its proper divisors (277412700).

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

131405220 is a wasteful number, since it uses less digits than its factorization.

131405220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 243361 (or 243353 counting only the distinct ones).

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

The square root of 131405220 is about 11463.2115918708. The cubic root of 131405220 is about 508.3984360466.

Adding to 131405220 its reverse (22504131), we get a palindrome (153909351).

The spelling of 131405220 in words is "one hundred thirty-one million, four hundred five thousand, two hundred twenty".