1211986 has 4 divisors (see below), whose sum is σ = 1817982. Its totient is φ = 605992.

The previous prime is 1211983. The next prime is 1211999. The reversal of 1211986 is 6891121.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 6891121 = 107 ⋅64403.

It can be written as a sum of positive squares in only one way, i.e., 748225 + 463761 = 865^2 + 681^2 .

It is not an unprimeable number, because it can be changed into a prime (1211983) 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, 302995 + ... + 302998.

2^1211986 is an apocalyptic number.

1211986 is a deficient number, since it is larger than the sum of its proper divisors (605996).

1211986 is an equidigital number, since it uses as much as digits as its factorization.

1211986 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 605995.

The product of its digits is 864, while the sum is 28.

The square root of 1211986 is about 1100.9023571598. The cubic root of 1211986 is about 106.6184917004.

It can be divided in two parts, 1211 and 986, that added together give a cube (2197 = 13³).

The spelling of 1211986 in words is "one million, two hundred eleven thousand, nine hundred eighty-six".