2661639 has 8 divisors (see below), whose sum is σ = 3757680. Its totient is φ = 1670016.

The previous prime is 2661611. The next prime is 2661641. The reversal of 2661639 is 9361662.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 2661639 - 2¹⁹ = 2137351 is a prime.

It is a super-3 number, since 3×2661639³ = 56567724499333380357, which contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2661689) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 26044 + ... + 26145.

It is an arithmetic number, because the mean of its divisors is an integer number (469710).

2^2661639 is an apocalyptic number.

2661639 is a deficient number, since it is larger than the sum of its proper divisors (1096041).

2661639 is a wasteful number, since it uses less digits than its factorization.

2661639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52209.

The product of its digits is 11664, while the sum is 33.

The square root of 2661639 is about 1631.4530333418. The cubic root of 2661639 is about 138.5850503085.

The spelling of 2661639 in words is "two million, six hundred sixty-one thousand, six hundred thirty-nine".