8899779991 has 2 divisors, whose sum is σ = 8899779992. Its totient is φ = 8899779990.

The previous prime is 8899779953. The next prime is 8899780009. The reversal of 8899779991 is 1999779988.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 8899779991 - 2¹⁵ = 8899747223 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8899773991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4449889995 + 4449889996.

It is an arithmetic number, because the mean of its divisors is an integer number (4449889996).

Almost surely, 2^8899779991 is an apocalyptic number.

8899779991 is a deficient number, since it is larger than the sum of its proper divisors (1).

8899779991 is an equidigital number, since it uses as much as digits as its factorization.

8899779991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 185177664, while the sum is 76.

The square root of 8899779991 is about 94338.6452679918. The cubic root of 8899779991 is about 2072.3340216679.

The spelling of 8899779991 in words is "eight billion, eight hundred ninety-nine million, seven hundred seventy-nine thousand, nine hundred ninety-one".