251493940 has 24 divisors (see below), whose sum is σ = 529302312. Its totient is φ = 100375680.

The previous prime is 251493929. The next prime is 251493941. The reversal of 251493940 is 49394152.

It can be written as a sum of positive squares in 4 ways, for example, as 1411344 + 250082596 = 1188^2 + 15814^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 251493940.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (251493941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4419 + ... + 22858.

It is an arithmetic number, because the mean of its divisors is an integer number (22054263).

Almost surely, 2^251493940 is an apocalyptic number.

251493940 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

251493940 is an abundant number, since it is smaller than the sum of its proper divisors (277808372).

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

251493940 is a wasteful number, since it uses less digits than its factorization.

251493940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27747 (or 27745 counting only the distinct ones).

The product of its (nonzero) digits is 38880, while the sum is 37.

The square root of 251493940 is about 15858.5604643044. The cubic root of 251493940 is about 631.2128646586.

The spelling of 251493940 in words is "two hundred fifty-one million, four hundred ninety-three thousand, nine hundred forty".