31189840 has 120 divisors (see below), whose sum is σ = 83932128. Its totient is φ = 10686720.

The previous prime is 31189801. The next prime is 31189841. The reversal of 31189840 is 4898113.

It is a happy number.

It is a super-2 number, since 2×31189840² = 1945612238451200, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 31189796 and 31189805.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31189841) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 465487 + ... + 465553.

Almost surely, 2^31189840 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 31189840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41966064).

31189840 is an abundant number, since it is smaller than the sum of its proper divisors (52742288).

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

31189840 is a wasteful number, since it uses less digits than its factorization.

31189840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 137 (or 108 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 34.

The square root of 31189840 is about 5584.7864775656. The cubic root of 31189840 is about 314.7780076956.

The spelling of 31189840 in words is "thirty-one million, one hundred eighty-nine thousand, eight hundred forty".