102100991 has 2 divisors, whose sum is σ = 102100992. Its totient is φ = 102100990.

The previous prime is 102100981. The next prime is 102101033. The reversal of 102100991 is 199001201.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-102100991 is a prime.

It is a super-2 number, since 2×102100991² = 20849224726364162, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (102100931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 51050495 + 51050496.

It is an arithmetic number, because the mean of its divisors is an integer number (51050496).

Almost surely, 2^102100991 is an apocalyptic number.

102100991 is a deficient number, since it is larger than the sum of its proper divisors (1).

102100991 is an equidigital number, since it uses as much as digits as its factorization.

102100991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 162, while the sum is 23.

The square root of 102100991 is about 10104.5035009148. The cubic root of 102100991 is about 467.3870256147.

The spelling of 102100991 in words is "one hundred two million, one hundred thousand, nine hundred ninety-one".