1021868191 has 2 divisors, whose sum is σ = 1021868192. Its totient is φ = 1021868190.

The previous prime is 1021868179. The next prime is 1021868209. The reversal of 1021868191 is 1918681201.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1021868191 - 2⁷ = 1021868063 is a prime.

It is a super-2 number, since 2×1021868191² = 2088429199555224962, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1021868191.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1021668191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 510934095 + 510934096.

It is an arithmetic number, because the mean of its divisors is an integer number (510934096).

Almost surely, 2^1021868191 is an apocalyptic number.

1021868191 is a deficient number, since it is larger than the sum of its proper divisors (1).

1021868191 is an equidigital number, since it uses as much as digits as its factorization.

1021868191 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6912, while the sum is 37.

The square root of 1021868191 is about 31966.6731299959. The cubic root of 1021868191 is about 1007.2368979692.

The spelling of 1021868191 in words is "one billion, twenty-one million, eight hundred sixty-eight thousand, one hundred ninety-one".