131221100 has 18 divisors (see below), whose sum is σ = 284750004. Its totient is φ = 52488400.

The previous prime is 131221093. The next prime is 131221117. The reversal of 131221100 is 1122131.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 656006 + ... + 656205.

Almost surely, 2^131221100 is an apocalyptic number.

131221100 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

131221100 is an abundant number, since it is smaller than the sum of its proper divisors (153528904).

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

131221100 is a wasteful number, since it uses less digits than its factorization.

131221100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1312225 (or 1312218 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 11.

The square root of 131221100 is about 11455.1778685449. The cubic root of 131221100 is about 508.1608755364.

Adding to 131221100 its reverse (1122131), we get a palindrome (132343231).

The spelling of 131221100 in words is "one hundred thirty-one million, two hundred twenty-one thousand, one hundred".