1261005055 has 8 divisors (see below), whose sum is σ = 1517544000. Its totient is φ = 1005912096.

The previous prime is 1261005047. The next prime is 1261005071. The reversal of 1261005055 is 5505001621.

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 1261005055 - 2³ = 1261005047 is a prime.

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, 359575 + ... + 363064.

It is an arithmetic number, because the mean of its divisors is an integer number (189693000).

Almost surely, 2^1261005055 is an apocalyptic number.

1261005055 is a deficient number, since it is larger than the sum of its proper divisors (256538945).

1261005055 is an equidigital number, since it uses as much as digits as its factorization.

1261005055 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 722993.

The product of its (nonzero) digits is 1500, while the sum is 25.

The square root of 1261005055 is about 35510.6329850652. The cubic root of 1261005055 is about 1080.3694023849.

Adding to 1261005055 its reverse (5505001621), we get a palindrome (6766006676).

The spelling of 1261005055 in words is "one billion, two hundred sixty-one million, five thousand, fifty-five".