989972791 has 2 divisors, whose sum is σ = 989972792. Its totient is φ = 989972790.

The previous prime is 989972749. The next prime is 989972807. The reversal of 989972791 is 197279989.

989972791 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is an emirp because it is prime and its reverse (197279989) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-989972791 is a prime.

It is a super-2 number, since 2×989972791² = 1960092253840659362, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (989973791) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 494986395 + 494986396.

It is an arithmetic number, because the mean of its divisors is an integer number (494986396).

Almost surely, 2^989972791 is an apocalyptic number.

989972791 is a deficient number, since it is larger than the sum of its proper divisors (1).

989972791 is an equidigital number, since it uses as much as digits as its factorization.

989972791 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5143824, while the sum is 61.

The square root of 989972791 is about 31463.8330627405. The cubic root of 989972791 is about 996.6463626894.

The spelling of 989972791 in words is "nine hundred eighty-nine million, nine hundred seventy-two thousand, seven hundred ninety-one".