2661691 has 8 divisors (see below), whose sum is σ = 2892800. Its totient is φ = 2439720.

The previous prime is 2661689. The next prime is 2661731. The reversal of 2661691 is 1961662.

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

It is a cyclic number.

It is not a de Polignac number, because 2661691 - 2¹ = 2661689 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2661611) 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, 1671 + ... + 2848.

It is an arithmetic number, because the mean of its divisors is an integer number (361600).

2^2661691 is an apocalyptic number.

2661691 is a deficient number, since it is larger than the sum of its proper divisors (231109).

2661691 is a wasteful number, since it uses less digits than its factorization.

2661691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4569.

The product of its digits is 3888, while the sum is 31.

The square root of 2661691 is about 1631.4689699777. The cubic root of 2661691 is about 138.5859528070.

The spelling of 2661691 in words is "two million, six hundred sixty-one thousand, six hundred ninety-one".