1861407 has 16 divisors (see below), whose sum is σ = 2799360. Its totient is φ = 1222200.

The previous prime is 1861403. The next prime is 1861417. The reversal of 1861407 is 7041681.

It is a happy number.

It is not a de Polignac number, because 1861407 - 2² = 1861403 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a zygodrome in base 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1861403) 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 15 ways as a sum of consecutive naturals, for example, 1432 + ... + 2402.

It is an arithmetic number, because the mean of its divisors is an integer number (174960).

2^1861407 is an apocalyptic number.

1861407 is a deficient number, since it is larger than the sum of its proper divisors (937953).

1861407 is an equidigital number, since it uses as much as digits as its factorization.

1861407 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1051 (or 1045 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 27.

The square root of 1861407 is about 1364.3339034122. Note that the first 3 decimals coincide. The cubic root of 1861407 is about 123.0118965293.

It can be divided in two parts, 18 and 61407, that added together give a triangular number (61425 = T₃₅₀).

The spelling of 1861407 in words is "one million, eight hundred sixty-one thousand, four hundred seven".