31687740 has 192 divisors, whose sum is σ = 115153920. Its totient is φ = 7084800.

The previous prime is 31687727. The next prime is 31687753. The reversal of 31687740 is 4778613.

It is an interprime number because it is at equal distance from previous prime (31687727) and next prime (31687753).

It is a super-2 number, since 2×31687740² = 2008225732615200, which contains 22 as substring.

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 = 31687695 and 31687704.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 313690 + ... + 313790.

It is an arithmetic number, because the mean of its divisors is an integer number (599760).

Almost surely, 2^31687740 is an apocalyptic number.

31687740 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 31687740, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (57576960).

31687740 is an abundant number, since it is smaller than the sum of its proper divisors (83466180).

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

31687740 is a wasteful number, since it uses less digits than its factorization.

31687740 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 209 (or 201 counting only the distinct ones).

The product of its (nonzero) digits is 28224, while the sum is 36.

The square root of 31687740 is about 5629.1864421069. The cubic root of 31687740 is about 316.4441625627. Note that the first 3 decimals are identical.

The spelling of 31687740 in words is "thirty-one million, six hundred eighty-seven thousand, seven hundred forty".