251243740 has 24 divisors (see below), whose sum is σ = 575577072. Its totient is φ = 91361280.

The previous prime is 251243701. The next prime is 251243749. The reversal of 251243740 is 47342152.

It is a junction number, because it is equal to n+sod(n) for n = 251243699 and 251243708.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (251243749) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 570789 + ... + 571228.

It is an arithmetic number, because the mean of its divisors is an integer number (23982378).

Almost surely, 2^251243740 is an apocalyptic number.

251243740 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

251243740 is an abundant number, since it is smaller than the sum of its proper divisors (324333332).

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

251243740 is a wasteful number, since it uses less digits than its factorization.

251243740 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1142037 (or 1142035 counting only the distinct ones).

The product of its (nonzero) digits is 6720, while the sum is 28.

The square root of 251243740 is about 15850.6700173841. The cubic root of 251243740 is about 631.0034734502.

Adding to 251243740 its reverse (47342152), we get a palindrome (298585892).

The spelling of 251243740 in words is "two hundred fifty-one million, two hundred forty-three thousand, seven hundred forty".