31440040 has 16 divisors (see below), whose sum is σ = 70740180. Its totient is φ = 12576000.

The previous prime is 31440001. The next prime is 31440049. The reversal of 31440040 is 4004413.

It can be written as a sum of positive squares in 2 ways, for example, as 30980356 + 459684 = 5566^2 + 678^2 .

It is a super-2 number, since 2×31440040² = 1976952230403200, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 31439996 and 31440023.

It is not an unprimeable number, because it can be changed into a prime (31440049) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 392961 + ... + 393040.

Almost surely, 2^31440040 is an apocalyptic number.

It is an amenable number.

31440040 is an abundant number, since it is smaller than the sum of its proper divisors (39300140).

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

31440040 is a wasteful number, since it uses less digits than its factorization.

31440040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 786012 (or 786008 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 16.

The square root of 31440040 is about 5607.1418744312. The cubic root of 31440040 is about 315.6174669313.

Adding to 31440040 its reverse (4004413), we get a palindrome (35444453).

The spelling of 31440040 in words is "thirty-one million, four hundred forty thousand, forty".