31213040 has 40 divisors (see below), whose sum is σ = 73307808. Its totient is φ = 12358400.

The previous prime is 31213027. The next prime is 31213043. The reversal of 31213040 is 4031213.

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-3 number, since 3×31213040³ (a number of 23 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31213043) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 6149 + ... + 10011.

Almost surely, 2^31213040 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 31213040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36653904).

31213040 is an abundant number, since it is smaller than the sum of its proper divisors (42094768).

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

31213040 is a wasteful number, since it uses less digits than its factorization.

31213040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3977 (or 3971 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 14.

The square root of 31213040 is about 5586.8631628133. The cubic root of 31213040 is about 314.8560356670.

Adding to 31213040 its reverse (4031213), we get a palindrome (35244253).

The spelling of 31213040 in words is "thirty-one million, two hundred thirteen thousand, forty".