251440040 has 32 divisors (see below), whose sum is σ = 568719360. Its totient is φ = 100046400.

The previous prime is 251440031. The next prime is 251440067. The reversal of 251440040 is 40044152.

251440040 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 251439994 and 251440021.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8816 + ... + 24095.

It is an arithmetic number, because the mean of its divisors is an integer number (17772480).

Almost surely, 2^251440040 is an apocalyptic number.

251440040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

251440040 is an abundant number, since it is smaller than the sum of its proper divisors (317279320).

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

251440040 is a wasteful number, since it uses less digits than its factorization.

251440040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33113 (or 33109 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 20.

The square root of 251440040 is about 15856.8609756156. The cubic root of 251440040 is about 631.1677677413.

Adding to 251440040 its reverse (40044152), we get a palindrome (291484192).

The spelling of 251440040 in words is "two hundred fifty-one million, four hundred forty thousand, forty".