102201991 has 2 divisors, whose sum is σ = 102201992. Its totient is φ = 102201990.

The previous prime is 102201973. The next prime is 102202021. The reversal of 102201991 is 199102201.

It is a weak prime.

It is an emirp because it is prime and its reverse (199102201) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 102201991 - 2¹¹ = 102199943 is a prime.

It is the 10110-th Hogben number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (102201941) by changing a digit.

It is a nontrivial repunit in base 10109.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 51100995 + 51100996.

It is an arithmetic number, because the mean of its divisors is an integer number (51100996).

Almost surely, 2^102201991 is an apocalyptic number.

102201991 is a deficient number, since it is larger than the sum of its proper divisors (1).

102201991 is an equidigital number, since it uses as much as digits as its factorization.

102201991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 324, while the sum is 25.

The square root of 102201991 is about 10109.5000370938. The cubic root of 102201991 is about 467.5410905002.

The spelling of 102201991 in words is "one hundred two million, two hundred one thousand, nine hundred ninety-one".