1251245555 has 16 divisors (see below), whose sum is σ = 1716899520. Its totient is φ = 857544192.

The previous prime is 1251245537. The next prime is 1251245557. The reversal of 1251245555 is 5555421521.

It is a cyclic number.

It is not a de Polignac number, because 1251245555 - 2⁶ = 1251245491 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is not an unprimeable number, because it can be changed into a prime (1251245557) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 66431 + ... + 83159.

It is an arithmetic number, because the mean of its divisors is an integer number (107306220).

Almost surely, 2^1251245555 is an apocalyptic number.

1251245555 is a deficient number, since it is larger than the sum of its proper divisors (465653965).

1251245555 is a wasteful number, since it uses less digits than its factorization.

1251245555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18878.

The product of its digits is 50000, while the sum is 35.

The square root of 1251245555 is about 35372.9494812067. The cubic root of 1251245555 is about 1077.5750218273.

The spelling of 1251245555 in words is "one billion, two hundred fifty-one million, two hundred forty-five thousand, five hundred fifty-five".