31440400 has 60 divisors (see below), whose sum is σ = 76526352. Its totient is φ = 12411520.

The previous prime is 31440371. The next prime is 31440401. The reversal of 31440400 is 404413.

It is a Harshad number since it is a multiple of its sum of digits (16).

It is not an unprimeable number, because it can be changed into a prime (31440401) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 32727 + ... + 33673.

Almost surely, 2^31440400 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 31440400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38263176).

31440400 is an abundant number, since it is smaller than the sum of its proper divisors (45085952).

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

31440400 is a wasteful number, since it uses less digits than its factorization.

31440400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1048 (or 1037 counting only the distinct ones).

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

The square root of 31440400 is about 5607.1739762558. The cubic root of 31440400 is about 315.6186715720.

Adding to 31440400 its reverse (404413), we get a palindrome (31844813).

The spelling of 31440400 in words is "thirty-one million, four hundred forty thousand, four hundred".