981912779 has 4 divisors (see below), whose sum is σ = 982030560. Its totient is φ = 981795000.

The previous prime is 981912721. The next prime is 981912781. The reversal of 981912779 is 977219189.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-981912779 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 981912779.

It is not an unprimeable number, because it can be changed into a prime (981911779) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 45347 + ... + 63404.

It is an arithmetic number, because the mean of its divisors is an integer number (245507640).

Almost surely, 2^981912779 is an apocalyptic number.

981912779 is a deficient number, since it is larger than the sum of its proper divisors (117781).

981912779 is a wasteful number, since it uses less digits than its factorization.

981912779 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 117780.

The product of its digits is 571536, while the sum is 53.

The square root of 981912779 is about 31335.4875341042. The cubic root of 981912779 is about 993.9342068818.

The spelling of 981912779 in words is "nine hundred eighty-one million, nine hundred twelve thousand, seven hundred seventy-nine".