1866989 has 2 divisors, whose sum is σ = 1866990. Its totient is φ = 1866988.

The previous prime is 1866973. The next prime is 1867001. The reversal of 1866989 is 9896681.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1646089 + 220900 = 1283^2 + 470^2 .

It is an emirp because it is prime and its reverse (9896681) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1866989 - 2⁴ = 1866973 is a prime.

It is a super-2 number, since 2×1866989² = 6971295852242, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1868989) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 933494 + 933495.

It is an arithmetic number, because the mean of its divisors is an integer number (933495).

2^1866989 is an apocalyptic number.

It is an amenable number.

1866989 is a deficient number, since it is larger than the sum of its proper divisors (1).

1866989 is an equidigital number, since it uses as much as digits as its factorization.

1866989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 186624, while the sum is 47.

The square root of 1866989 is about 1366.3780589573. The cubic root of 1866989 is about 123.1347367909.

The spelling of 1866989 in words is "one million, eight hundred sixty-six thousand, nine hundred eighty-nine".