31440020 has 24 divisors (see below), whose sum is σ = 66130344. Its totient is φ = 12555776.

The previous prime is 31440001. The next prime is 31440049. The reversal of 31440020 is 2004413.

It can be written as a sum of positive squares in 4 ways, for example, as 4545424 + 26894596 = 2132^2 + 5186^2 .

It is a junction number, because it is equal to n+sod(n) for n = 31439977 and 31440004.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21224 + ... + 22656.

It is an arithmetic number, because the mean of its divisors is an integer number (2755431).

Almost surely, 2^31440020 is an apocalyptic number.

It is an amenable number.

31440020 is an abundant number, since it is smaller than the sum of its proper divisors (34690324).

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

31440020 is a wasteful number, since it uses less digits than its factorization.

31440020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2539 (or 2537 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 14.

The square root of 31440020 is about 5607.1400909911. The cubic root of 31440020 is about 315.6174000065.

Adding to 31440020 its reverse (2004413), we get a palindrome (33444433).

The spelling of 31440020 in words is "thirty-one million, four hundred forty thousand, twenty".