1261251655 has 8 divisors (see below), whose sum is σ = 1514332512. Its totient is φ = 1008447648.

The previous prime is 1261251643. The next prime is 1261251679. The reversal of 1261251655 is 5561521621.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1261251655 - 2⁵ = 1261251623 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1261251655.

It is a congruent number.

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, 59052 + ... + 77521.

It is an arithmetic number, because the mean of its divisors is an integer number (189291564).

Almost surely, 2^1261251655 is an apocalyptic number.

1261251655 is a deficient number, since it is larger than the sum of its proper divisors (253080857).

1261251655 is a wasteful number, since it uses less digits than its factorization.

1261251655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 138425.

The product of its digits is 18000, while the sum is 34.

The square root of 1261251655 is about 35514.1050147684. The cubic root of 1261251655 is about 1080.4398228612.

The spelling of 1261251655 in words is "one billion, two hundred sixty-one million, two hundred fifty-one thousand, six hundred fifty-five".