131221332 has 36 divisors (see below), whose sum is σ = 361853856. Its totient is φ = 39763920.

The previous prime is 131221327. The next prime is 131221339. The reversal of 131221332 is 233122131.

131221332 is a `hidden beast` number, since 1 + 312 + 21 + 332 = 666.

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 (18).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (131221339) 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, 165288 + ... + 166079.

It is an arithmetic number, because the mean of its divisors is an integer number (10051496).

Almost surely, 2^131221332 is an apocalyptic number.

131221332 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

131221332 is an abundant number, since it is smaller than the sum of its proper divisors (230632524).

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

131221332 is a wasteful number, since it uses less digits than its factorization.

131221332 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 331388 (or 331383 counting only the distinct ones).

The product of its digits is 216, while the sum is 18.

The square root of 131221332 is about 11455.1879949654. The cubic root of 131221332 is about 508.1611750138.

Adding to 131221332 its reverse (233122131), we get a palindrome (364343463).

The spelling of 131221332 in words is "one hundred thirty-one million, two hundred twenty-one thousand, three hundred thirty-two".