1861993 has 8 divisors (see below), whose sum is σ = 2253312. Its totient is φ = 1502016.

The previous prime is 1861991. The next prime is 1862009. The reversal of 1861993 is 3991681.

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 1861993 - 2¹ = 1861991 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1861991) 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 in 7 ways as a sum of consecutive naturals, for example, 7705 + ... + 7942.

It is an arithmetic number, because the mean of its divisors is an integer number (281664).

2^1861993 is an apocalyptic number.

It is an amenable number.

1861993 is a deficient number, since it is larger than the sum of its proper divisors (391319).

1861993 is a wasteful number, since it uses less digits than its factorization.

1861993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15671.

The product of its digits is 11664, while the sum is 37.

The square root of 1861993 is about 1364.5486433250. The cubic root of 1861993 is about 123.0248038638.

The spelling of 1861993 in words is "one million, eight hundred sixty-one thousand, nine hundred ninety-three".