99910091 has 4 divisors (see below), whose sum is σ = 104254032. Its totient is φ = 95566152.

The previous prime is 99910087. The next prime is 99910093. The reversal of 99910091 is 19001999.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 99910091 - 2² = 99910087 is a prime.

It is not an unprimeable number, because it can be changed into a prime (99910093) 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, 2171936 + ... + 2171981.

It is an arithmetic number, because the mean of its divisors is an integer number (26063508).

Almost surely, 2^99910091 is an apocalyptic number.

99910091 is a deficient number, since it is larger than the sum of its proper divisors (4343941).

99910091 is a wasteful number, since it uses less digits than its factorization.

99910091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4343940.

The product of its (nonzero) digits is 6561, while the sum is 38.

The square root of 99910091 is about 9995.5035390920. The cubic root of 99910091 is about 464.0197347804.

It can be divided in two parts, 99 and 910091, that multiplied together give a palindrome (90099009).

The spelling of 99910091 in words is "ninety-nine million, nine hundred ten thousand, ninety-one".