1251555555 has 32 divisors (see below), whose sum is σ = 2231884800. Its totient is φ = 595164672.

The previous prime is 1251555551. The next prime is 1251555559. The reversal of 1251555555 is 5555551521.

It is an interprime number because it is at equal distance from previous prime (1251555551) and next prime (1251555559).

It is not a de Polignac number, because 1251555555 - 2² = 1251555551 is a prime.

1251555555 is a modest number, since divided by 55555 gives 12515 as remainder.

It is not an unprimeable number, because it can be changed into a prime (1251555551) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 124315 + ... + 134004.

It is an arithmetic number, because the mean of its divisors is an integer number (69746400).

Almost surely, 2^1251555555 is an apocalyptic number.

1251555555 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1251555555 is a deficient number, since it is larger than the sum of its proper divisors (980329245).

1251555555 is a wasteful number, since it uses less digits than its factorization.

1251555555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 258363.

The product of its digits is 156250, while the sum is 39.

The square root of 1251555555 is about 35377.3310892724. The cubic root of 1251555555 is about 1077.6640053398.

The spelling of 1251555555 in words is "one billion, two hundred fifty-one million, five hundred fifty-five thousand, five hundred fifty-five".