31020240 has 80 divisors (see below), whose sum is σ = 101832768. Its totient is φ = 7784448.

The previous prime is 31020233. The next prime is 31020247. The reversal of 31020240 is 4202013.

It is an interprime number because it is at equal distance from previous prime (31020233) and next prime (31020247).

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31020247) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 279 + ... + 7881.

Almost surely, 2^31020240 is an apocalyptic number.

31020240 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 31020240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (50916384).

31020240 is an abundant number, since it is smaller than the sum of its proper divisors (70812528).

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

31020240 is a wasteful number, since it uses less digits than its factorization.

31020240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7636 (or 7630 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 12.

The square root of 31020240 is about 5569.5816719032. The cubic root of 31020240 is about 314.2064176175.

Adding to 31020240 its reverse (4202013), we get a palindrome (35222253).

The spelling of 31020240 in words is "thirty-one million, twenty thousand, two hundred forty".