1251260640 has 144 divisors (see below), whose sum is σ = 4879955808. Its totient is φ = 286000128.

The previous prime is 1251260603. The next prime is 1251260671. The reversal of 1251260640 is 460621521.

1251260640 is a `hidden beast` number, since 1 + 2 + 5 + 12 + 6 + 0 + 640 = 666.

It is a tau number, because it is divible by the number of its divisors (144).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 51987 + ... + 72146.

It is an arithmetic number, because the mean of its divisors is an integer number (33888582).

Almost surely, 2^1251260640 is an apocalyptic number.

1251260640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1251260640 is an abundant number, since it is smaller than the sum of its proper divisors (3628695168).

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

1251260640 is a wasteful number, since it uses less digits than its factorization.

1251260640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 124161 (or 124150 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

The square root of 1251260640 is about 35373.1627084715. The cubic root of 1251260640 is about 1077.5793522200.

The spelling of 1251260640 in words is "one billion, two hundred fifty-one million, two hundred sixty thousand, six hundred forty".