101899991 has 2 divisors, whose sum is σ = 101899992. Its totient is φ = 101899990.

The previous prime is 101899979. The next prime is 101899999. The reversal of 101899991 is 199998101.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-101899991 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (101899999) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 50949995 + 50949996.

It is an arithmetic number, because the mean of its divisors is an integer number (50949996).

Almost surely, 2^101899991 is an apocalyptic number.

101899991 is a deficient number, since it is larger than the sum of its proper divisors (1).

101899991 is an equidigital number, since it uses as much as digits as its factorization.

101899991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 52488, while the sum is 47.

The square root of 101899991 is about 10094.5525408509. The cubic root of 101899991 is about 467.0801186770.

The spelling of 101899991 in words is "one hundred one million, eight hundred ninety-nine thousand, nine hundred ninety-one".