31243290 has 32 divisors (see below), whose sum is σ = 80752896. Its totient is φ = 7690560.

The previous prime is 31243283. The next prime is 31243301. The reversal of 31243290 is 9234213.

Added to its reverse (9234213) it gives a triangular number (40477503 = T₈₉₉₇).

It is a super-2 number, since 2×31243290² = 1952286340048200, which contains 22 as substring.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 31243290.

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, 39666 + ... + 40445.

It is an arithmetic number, because the mean of its divisors is an integer number (2523528).

Almost surely, 2^31243290 is an apocalyptic number.

31243290 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

31243290 is an abundant number, since it is smaller than the sum of its proper divisors (49509606).

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

31243290 is a wasteful number, since it uses less digits than its factorization.

31243290 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80134.

The product of its (nonzero) digits is 1296, while the sum is 24.

The square root of 31243290 is about 5589.5697508842. The cubic root of 31243290 is about 314.9577166726.

Adding to 31243290 its reverse (9234213), we get a triangular number (40477503 = T₈₉₉₇).

The spelling of 31243290 in words is "thirty-one million, two hundred forty-three thousand, two hundred ninety".