99891251 has 2 divisors, whose sum is σ = 99891252. Its totient is φ = 99891250.

The previous prime is 99891191. The next prime is 99891271. The reversal of 99891251 is 15219899.

It is a happy number.

It is a strong prime.

It is an emirp because it is prime and its reverse (15219899) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 99891251 - 2¹⁴ = 99874867 is a prime.

It is not a weakly prime, because it can be changed into another prime (99891271) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49945625 + 49945626.

It is an arithmetic number, because the mean of its divisors is an integer number (49945626).

Almost surely, 2^99891251 is an apocalyptic number.

99891251 is a deficient number, since it is larger than the sum of its proper divisors (1).

99891251 is an equidigital number, since it uses as much as digits as its factorization.

99891251 is an evil number, because the sum of its binary digits is even.

The product of its digits is 58320, while the sum is 44.

The square root of 99891251 is about 9994.5610709025. The cubic root of 99891251 is about 463.9905662841.

The spelling of 99891251 in words is "ninety-nine million, eight hundred ninety-one thousand, two hundred fifty-one".