31679840 has 96 divisors (see below), whose sum is σ = 83553120. Its totient is φ = 11280384.

The previous prime is 31679827. The next prime is 31679899. The reversal of 31679840 is 4897613.

31679840 = T₃₁ + T₃₂ + ... + T₅₇₄.

It is a super-2 number, since 2×31679840² = 2007224524851200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (38).

It is a junction number, because it is equal to n+sod(n) for n = 31679794 and 31679803.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 51374 + ... + 51986.

It is an arithmetic number, because the mean of its divisors is an integer number (870345).

Almost surely, 2^31679840 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31679840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41776560).

31679840 is an abundant number, since it is smaller than the sum of its proper divisors (51873280).

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

31679840 is a wasteful number, since it uses less digits than its factorization.

31679840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 664 (or 656 counting only the distinct ones).

The product of its (nonzero) digits is 36288, while the sum is 38.

The square root of 31679840 is about 5628.4846983891. The cubic root of 31679840 is about 316.4178630468.

The spelling of 31679840 in words is "thirty-one million, six hundred seventy-nine thousand, eight hundred forty".