2780661 has 32 divisors (see below), whose sum is σ = 4290048. Its totient is φ = 1589760.

The previous prime is 2780647. The next prime is 2780671. The reversal of 2780661 is 1660872.

It is a happy number.

It is not a de Polignac number, because 2780661 - 2⁶ = 2780597 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2780621) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 59140 + ... + 59186.

It is an arithmetic number, because the mean of its divisors is an integer number (134064).

2^2780661 is an apocalyptic number.

It is an amenable number.

2780661 is a deficient number, since it is larger than the sum of its proper divisors (1509387).

2780661 is a wasteful number, since it uses less digits than its factorization.

2780661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 141.

The product of its (nonzero) digits is 4032, while the sum is 30.

The square root of 2780661 is about 1667.5314089995. The cubic root of 2780661 is about 140.6207301420.

The spelling of 2780661 in words is "two million, seven hundred eighty thousand, six hundred sixty-one".