99051991 has 2 divisors, whose sum is σ = 99051992. Its totient is φ = 99051990.

The previous prime is 99051949. The next prime is 99052033. The reversal of 99051991 is 19915099.

It is a balanced prime because it is at equal distance from previous prime (99051949) and next prime (99052033).

It is an emirp because it is prime and its reverse (19915099) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 99051991 - 2⁷ = 99051863 is a prime.

It is a super-2 number, since 2×99051991² = 19622593842128162, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (99051391) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49525995 + 49525996.

It is an arithmetic number, because the mean of its divisors is an integer number (49525996).

Almost surely, 2^99051991 is an apocalyptic number.

99051991 is a deficient number, since it is larger than the sum of its proper divisors (1).

99051991 is an equidigital number, since it uses as much as digits as its factorization.

99051991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 32805, while the sum is 43.

The square root of 99051991 is about 9952.4866741935. The cubic root of 99051991 is about 462.6874678056.

The spelling of 99051991 in words is "ninety-nine million, fifty-one thousand, nine hundred ninety-one".