1806240661 has 4 divisors (see below), whose sum is σ = 1807206892. Its totient is φ = 1805274432.

The previous prime is 1806240647. The next prime is 1806240673. The reversal of 1806240661 is 1660426081.

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 118592100 + 1687648561 = 10890^2 + 41081^2 .

It is a cyclic number.

It is not a de Polignac number, because 1806240661 - 2¹⁹ = 1805716373 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 (1806240061) 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, 480306 + ... + 484051.

It is an arithmetic number, because the mean of its divisors is an integer number (451801723).

Almost surely, 2^1806240661 is an apocalyptic number.

It is an amenable number.

1806240661 is a deficient number, since it is larger than the sum of its proper divisors (966231).

1806240661 is an equidigital number, since it uses as much as digits as its factorization.

1806240661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 966230.

The product of its (nonzero) digits is 13824, while the sum is 34.

The square root of 1806240661 is about 42499.8901292697. The cubic root of 1806240661 is about 1217.8445909318.

The spelling of 1806240661 in words is "one billion, eight hundred six million, two hundred forty thousand, six hundred sixty-one".