2820661 has 4 divisors (see below), whose sum is σ = 2830912. Its totient is φ = 2810412.

The previous prime is 2820641. The next prime is 2820667. The reversal of 2820661 is 1660282.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2820661 is a prime.

It is a super-2 number, since 2×2820661² = 15912256953842, which contains 22 as substring.

It is a Duffinian number.

2820661 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2820667) 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, 4701 + ... + 5266.

It is an arithmetic number, because the mean of its divisors is an integer number (707728).

2^2820661 is an apocalyptic number.

It is an amenable number.

2820661 is a deficient number, since it is larger than the sum of its proper divisors (10251).

2820661 is an equidigital number, since it uses as much as digits as its factorization.

2820661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10250.

The product of its (nonzero) digits is 1152, while the sum is 25.

The square root of 2820661 is about 1679.4823607290. The cubic root of 2820661 is about 141.2918021785.

It can be divided in two parts, 2820 and 661, that added together give a square (3481 = 59²).

The spelling of 2820661 in words is "two million, eight hundred twenty thousand, six hundred sixty-one".