1891969 has 2 divisors, whose sum is σ = 1891970. Its totient is φ = 1891968.

The previous prime is 1891951. The next prime is 1891987. The reversal of 1891969 is 9691981.

It is a balanced prime because it is at equal distance from previous prime (1891951) and next prime (1891987).

It can be written as a sum of positive squares in only one way, i.e., 1809025 + 82944 = 1345^2 + 288^2 .

It is a cyclic number.

It is not a de Polignac number, because 1891969 - 2⁹ = 1891457 is a prime.

It is a super-2 number, since 2×1891969² = 7159093393922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1891909) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 945984 + 945985.

It is an arithmetic number, because the mean of its divisors is an integer number (945985).

2^1891969 is an apocalyptic number.

It is an amenable number.

1891969 is a deficient number, since it is larger than the sum of its proper divisors (1).

1891969 is an equidigital number, since it uses as much as digits as its factorization.

1891969 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 34992, while the sum is 43.

The square root of 1891969 is about 1375.4886404475. The cubic root of 1891969 is about 123.6814795995.

The spelling of 1891969 in words is "one million, eight hundred ninety-one thousand, nine hundred sixty-nine".