102661891 has 2 divisors, whose sum is σ = 102661892. Its totient is φ = 102661890.

The previous prime is 102661879. The next prime is 102661907. The reversal of 102661891 is 198166201.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-102661891 is a prime.

It is a zygodrome in base 2.

It is not a weakly prime, because it can be changed into another prime (102661831) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 51330945 + 51330946.

It is an arithmetic number, because the mean of its divisors is an integer number (51330946).

Almost surely, 2^102661891 is an apocalyptic number.

102661891 is a deficient number, since it is larger than the sum of its proper divisors (1).

102661891 is an equidigital number, since it uses as much as digits as its factorization.

102661891 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5184, while the sum is 34.

The square root of 102661891 is about 10132.2204377915. The cubic root of 102661891 is about 468.2413391691.

The spelling of 102661891 in words is "one hundred two million, six hundred sixty-one thousand, eight hundred ninety-one".