1618861 has 4 divisors (see below), whose sum is σ = 1662652. Its totient is φ = 1575072.

The previous prime is 1618853. The next prime is 1618891. The reversal of 1618861 is 1688161.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1142761 + 476100 = 1069^2 + 690^2 .

It is a cyclic number.

It is not a de Polignac number, because 1618861 - 2³ = 1618853 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1618831) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21840 + ... + 21913.

It is an arithmetic number, because the mean of its divisors is an integer number (415663).

2^1618861 is an apocalyptic number.

It is an amenable number.

1618861 is a deficient number, since it is larger than the sum of its proper divisors (43791).

1618861 is an equidigital number, since it uses as much as digits as its factorization.

1618861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43790.

The product of its digits is 2304, while the sum is 31.

The square root of 1618861 is about 1272.3446860030. The cubic root of 1618861 is about 117.4184978790.

The spelling of 1618861 in words is "one million, six hundred eighteen thousand, eight hundred sixty-one".