131978640 has 40 divisors (see below), whose sum is σ = 409134528. Its totient is φ = 35194240.

The previous prime is 131978621. The next prime is 131978659. The reversal of 131978640 is 46879131.

It is an interprime number because it is at equal distance from previous prime (131978621) and next prime (131978659).

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×131978640² = 34836722832499200, which contains 22 as substring.

It is a hoax number, since the sum of its digits (39) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 274716 + ... + 275195.

Almost surely, 2^131978640 is an apocalyptic number.

131978640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

131978640 is an abundant number, since it is smaller than the sum of its proper divisors (277155888).

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

131978640 is a wasteful number, since it uses less digits than its factorization.

131978640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 549927 (or 549921 counting only the distinct ones).

The product of its (nonzero) digits is 36288, while the sum is 39.

The square root of 131978640 is about 11488.1956807847. The cubic root of 131978640 is about 509.1368714687.

The spelling of 131978640 in words is "one hundred thirty-one million, nine hundred seventy-eight thousand, six hundred forty".