31440424 has 16 divisors (see below), whose sum is σ = 59279220. Its totient is φ = 15632640.

The previous prime is 31440419. The next prime is 31440427. The reversal of 31440424 is 42404413.

It can be written as a sum of positive squares in 2 ways, for example, as 25100100 + 6340324 = 5010^2 + 2518^2 .

It is a super-2 number, since 2×31440424² = 1977000522599552, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 31440395 and 31440404.

It is not an unprimeable number, because it can be changed into a prime (31440427) 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, 9409 + ... + 12304.

Almost surely, 2^31440424 is an apocalyptic number.

It is an amenable number.

31440424 is a deficient number, since it is larger than the sum of its proper divisors (27838796).

31440424 is a wasteful number, since it uses less digits than its factorization.

31440424 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21900 (or 21896 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 22.

The square root of 31440424 is about 5607.1761163709. The cubic root of 31440424 is about 315.6187518810.

Adding to 31440424 its reverse (42404413), we get a palindrome (73844837).

The spelling of 31440424 in words is "thirty-one million, four hundred forty thousand, four hundred twenty-four".