31481840 has 40 divisors (see below), whose sum is σ = 78828288. Its totient is φ = 11623680.

The previous prime is 31481837. The next prime is 31481843. The reversal of 31481840 is 4818413.

31481840 = 40² + 41² + ... + 455².

It is an interprime number because it is at equal distance from previous prime (31481837) and next prime (31481843).

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

It is a super-2 number, since 2×31481840² = 1982212499571200, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31481843) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14096 + ... + 16175.

Almost surely, 2^31481840 is an apocalyptic number.

It is an amenable number.

31481840 is an abundant number, since it is smaller than the sum of its proper divisors (47346448).

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

31481840 is a wasteful number, since it uses less digits than its factorization.

31481840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30297 (or 30291 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 29.

The square root of 31481840 is about 5610.8680255376. The cubic root of 31481840 is about 315.7572776923.

The spelling of 31481840 in words is "thirty-one million, four hundred eighty-one thousand, eight hundred forty".