1231866 has 12 divisors (see below), whose sum is σ = 2669082. Its totient is φ = 410616.

The previous prime is 1231859. The next prime is 1231873. The reversal of 1231866 is 6681321.

It is an interprime number because it is at equal distance from previous prime (1231859) and next prime (1231873).

It can be written as a sum of positive squares in only one way, i.e., 1010025 + 221841 = 1005^2 + 471^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 34201 + ... + 34236.

2^1231866 is an apocalyptic number.

1231866 is an abundant number, since it is smaller than the sum of its proper divisors (1437216).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1231866 is a wasteful number, since it uses less digits than its factorization.

1231866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68445 (or 68442 counting only the distinct ones).

The product of its digits is 1728, while the sum is 27.

The square root of 1231866 is about 1109.8945895895. The cubic root of 1231866 is about 107.1982814197.

It can be divided in two parts, 12 and 31866, that added together give a triangular number (31878 = T₂₅₂).

The spelling of 1231866 in words is "one million, two hundred thirty-one thousand, eight hundred sixty-six".