981261855 has 24 divisors (see below), whose sum is σ = 1943833632. Its totient is φ = 448576704.

The previous prime is 981261851. The next prime is 981261871. The reversal of 981261855 is 558162189.

It is a happy number.

It is not a de Polignac number, because 981261855 - 2² = 981261851 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 981261855.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (981261851) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1557244 + ... + 1557873.

It is an arithmetic number, because the mean of its divisors is an integer number (80993068).

Almost surely, 2^981261855 is an apocalyptic number.

981261855 is a deficient number, since it is larger than the sum of its proper divisors (962571777).

981261855 is a wasteful number, since it uses less digits than its factorization.

981261855 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3115135 (or 3115132 counting only the distinct ones).

The product of its digits is 172800, while the sum is 45.

The square root of 981261855 is about 31325.0994411829. The cubic root of 981261855 is about 993.7145272730.

The spelling of 981261855 in words is "nine hundred eighty-one million, two hundred sixty-one thousand, eight hundred fifty-five".