31305690 has 96 divisors (see below), whose sum is σ = 90994176. Its totient is φ = 7698240.

The previous prime is 31305671. The next prime is 31305731. The reversal of 31305690 is 9650313.

It is a super-2 number, since 2×31305690² = 1960092452752200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 31095 + ... + 32085.

It is an arithmetic number, because the mean of its divisors is an integer number (947856).

Almost surely, 2^31305690 is an apocalyptic number.

31305690 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 31305690, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45497088).

31305690 is an abundant number, since it is smaller than the sum of its proper divisors (59688486).

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

31305690 is a wasteful number, since it uses less digits than its factorization.

31305690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1026 (or 1014 counting only the distinct ones).

The product of its (nonzero) digits is 2430, while the sum is 27.

The square root of 31305690 is about 5595.1487915872. The cubic root of 31305690 is about 315.1672581127.

The spelling of 31305690 in words is "thirty-one million, three hundred five thousand, six hundred ninety".