1261127551 has 8 divisors (see below), whose sum is σ = 1265038544. Its totient is φ = 1257223680.

The previous prime is 1261127531. The next prime is 1261127563. The reversal of 1261127551 is 1557211621.

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 1261127551 - 2⁹ = 1261127039 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1261127531) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 744061 + ... + 745753.

It is an arithmetic number, because the mean of its divisors is an integer number (158129818).

Almost surely, 2^1261127551 is an apocalyptic number.

1261127551 is a deficient number, since it is larger than the sum of its proper divisors (3910993).

1261127551 is a wasteful number, since it uses less digits than its factorization.

1261127551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3561.

The product of its digits is 4200, while the sum is 31.

The square root of 1261127551 is about 35512.3577223479. The cubic root of 1261127551 is about 1080.4043841758.

The spelling of 1261127551 in words is "one billion, two hundred sixty-one million, one hundred twenty-seven thousand, five hundred fifty-one".