31299840 has 432 divisors, whose sum is σ = 133922880. Its totient is φ = 6635520.

The previous prime is 31299809. The next prime is 31299847. The reversal of 31299840 is 4899213.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 31299795 and 31299804.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31299847) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1647351 + ... + 1647369.

Almost surely, 2^31299840 is an apocalyptic number.

31299840 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31299840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (66961440).

31299840 is an abundant number, since it is smaller than the sum of its proper divisors (102623040).

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

31299840 is a wasteful number, since it uses less digits than its factorization.

31299840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70 (or 53 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 36.

The square root of 31299840 is about 5594.6259928614. The cubic root of 31299840 is about 315.1476254376.

The spelling of 31299840 in words is "thirty-one million, two hundred ninety-nine thousand, eight hundred forty".