251512040 has 128 divisors (see below), whose sum is σ = 640120320. Its totient is φ = 88320000.

The previous prime is 251512039. The next prime is 251512049. The reversal of 251512040 is 40215152.

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

It is not an unprimeable number, because it can be changed into a prime (251512049) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 1001915 + ... + 1002165.

It is an arithmetic number, because the mean of its divisors is an integer number (5000940).

Almost surely, 2^251512040 is an apocalyptic number.

251512040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 251512040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (320060160).

251512040 is an abundant number, since it is smaller than the sum of its proper divisors (388608280).

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

251512040 is a wasteful number, since it uses less digits than its factorization.

251512040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 363 (or 359 counting only the distinct ones).

The product of its (nonzero) digits is 400, while the sum is 20.

The square root of 251512040 is about 15859.1311237407. The cubic root of 251512040 is about 631.2280070761.

Adding to 251512040 its reverse (40215152), we get a palindrome (291727192).

The spelling of 251512040 in words is "two hundred fifty-one million, five hundred twelve thousand, forty".