31123890 has 96 divisors (see below), whose sum is σ = 93450240. Its totient is φ = 7039872.

The previous prime is 31123877. The next prime is 31123891. The reversal of 31123890 is 9832113.

It is not an unprimeable number, because it can be changed into a prime (31123891) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 79816 + ... + 80204.

It is an arithmetic number, because the mean of its divisors is an integer number (973440).

Almost surely, 2^31123890 is an apocalyptic number.

31123890 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 31123890, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (46725120).

31123890 is an abundant number, since it is smaller than the sum of its proper divisors (62326350).

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

31123890 is a wasteful number, since it uses less digits than its factorization.

31123890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 536 (or 533 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

The square root of 31123890 is about 5578.8789196397. The cubic root of 31123890 is about 314.5559881888. Note that the first 3 decimals are identical.

The spelling of 31123890 in words is "thirty-one million, one hundred twenty-three thousand, eight hundred ninety".