251243502240 has 48 divisors (see below), whose sum is σ = 791417033568. Its totient is φ = 66998267136.

The previous prime is 251243502221. The next prime is 251243502287. The reversal of 251243502240 is 42205342152.

It is a tau number, because it is divible by the number of its divisors (48).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 251243502198 and 251243502207.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 261711502 + ... + 261712461.

It is an arithmetic number, because the mean of its divisors is an integer number (16487854866).

Almost surely, 2^251243502240 is an apocalyptic number.

251243502240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

251243502240 is an abundant number, since it is smaller than the sum of its proper divisors (540173531328).

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

251243502240 is a wasteful number, since it uses less digits than its factorization.

251243502240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 523423981 (or 523423973 counting only the distinct ones).

The product of its (nonzero) digits is 19200, while the sum is 30.

Adding to 251243502240 its reverse (42205342152), we get a palindrome (293448844392).

The spelling of 251243502240 in words is "two hundred fifty-one billion, two hundred forty-three million, five hundred two thousand, two hundred forty".