99981251 has 2 divisors, whose sum is σ = 99981252. Its totient is φ = 99981250.

The previous prime is 99981229. The next prime is 99981317. The reversal of 99981251 is 15218999.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-99981251 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (99981221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49990625 + 49990626.

It is an arithmetic number, because the mean of its divisors is an integer number (49990626).

Almost surely, 2^99981251 is an apocalyptic number.

99981251 is a deficient number, since it is larger than the sum of its proper divisors (1).

99981251 is an equidigital number, since it uses as much as digits as its factorization.

99981251 is an odious number, because the sum of its binary digits is odd.

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

The square root of 99981251 is about 9999.0625060553. The cubic root of 99981251 is about 464.1298731651.

The spelling of 99981251 in words is "ninety-nine million, nine hundred eighty-one thousand, two hundred fifty-one".