2661999 has 4 divisors (see below), whose sum is σ = 3549336. Its totient is φ = 1774664.

The previous prime is 2661991. The next prime is 2662027. The reversal of 2661999 is 9991662.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 2661999 - 2³ = 2661991 is a prime.

It is a D-number.

It is a plaindrome in base 11.

It is a self number, because there is not a number n which added to its sum of digits gives 2661999.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2661991) 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 3 ways as a sum of consecutive naturals, for example, 443664 + ... + 443669.

It is an arithmetic number, because the mean of its divisors is an integer number (887334).

2^2661999 is an apocalyptic number.

2661999 is a deficient number, since it is larger than the sum of its proper divisors (887337).

2661999 is an equidigital number, since it uses as much as digits as its factorization.

2661999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 887336.

The product of its digits is 52488, while the sum is 42.

The square root of 2661999 is about 1631.5633607065. The cubic root of 2661999 is about 138.5912981341.

The spelling of 2661999 in words is "two million, six hundred sixty-one thousand, nine hundred ninety-nine".