989919851 has 2 divisors, whose sum is σ = 989919852. Its totient is φ = 989919850.

The previous prime is 989919803. The next prime is 989919859. The reversal of 989919851 is 158919989.

It is a strong prime.

It is an emirp because it is prime and its reverse (158919989) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 989919851 - 2⁶ = 989919787 is a prime.

It is a super-2 number, since 2×989919851² = 1959882622807724402, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (989919859) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 494959925 + 494959926.

It is an arithmetic number, because the mean of its divisors is an integer number (494959926).

Almost surely, 2^989919851 is an apocalyptic number.

989919851 is a deficient number, since it is larger than the sum of its proper divisors (1).

989919851 is an equidigital number, since it uses as much as digits as its factorization.

989919851 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2099520, while the sum is 59.

The square root of 989919851 is about 31462.9917681075. The cubic root of 989919851 is about 996.6285967470.

The spelling of 989919851 in words is "nine hundred eighty-nine million, nine hundred nineteen thousand, eight hundred fifty-one".