31355940 has 144 divisors (see below), whose sum is σ = 110468736. Its totient is φ = 6504960.

The previous prime is 31355917. The next prime is 31355957. The reversal of 31355940 is 4955313.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 31355898 and 31355907.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 50512 + ... + 51128.

It is an arithmetic number, because the mean of its divisors is an integer number (767144).

Almost surely, 2^31355940 is an apocalyptic number.

31355940 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 31355940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (55234368).

31355940 is an abundant number, since it is smaller than the sum of its proper divisors (79112796).

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

31355940 is a wasteful number, since it uses less digits than its factorization.

31355940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 658 (or 645 counting only the distinct ones).

The product of its (nonzero) digits is 8100, while the sum is 30.

The square root of 31355940 is about 5599.6374882665. The cubic root of 31355940 is about 315.3357971083.

The spelling of 31355940 in words is "thirty-one million, three hundred fifty-five thousand, nine hundred forty".