1866981 has 8 divisors (see below), whose sum is σ = 2542464. Its totient is φ = 1218080.

The previous prime is 1866973. The next prime is 1866989. The reversal of 1866981 is 1896681.

It is an interprime number because it is at equal distance from previous prime (1866973) and next prime (1866989).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1866981 - 2³ = 1866973 is a prime.

It is a super-2 number, since 2×1866981² = 6971236108722, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1866989) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 6480 + ... + 6761.

It is an arithmetic number, because the mean of its divisors is an integer number (317808).

2^1866981 is an apocalyptic number.

It is an amenable number.

1866981 is a deficient number, since it is larger than the sum of its proper divisors (675483).

1866981 is a wasteful number, since it uses less digits than its factorization.

1866981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13291.

The product of its digits is 20736, while the sum is 39.

The square root of 1866981 is about 1366.3751315067. The cubic root of 1866981 is about 123.1345609142.

It can be divided in two parts, 186 and 6981, that multiplied together give a triangular number (1298466 = T₁₆₁₁).

The spelling of 1866981 in words is "one million, eight hundred sixty-six thousand, nine hundred eighty-one".