7820661 has 4 divisors (see below), whose sum is σ = 10427552. Its totient is φ = 5213772.

The previous prime is 7820639. The next prime is 7820669. The reversal of 7820661 is 1660287.

It is a happy number.

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 not a de Polignac number, because 7820661 - 2⁶ = 7820597 is a prime.

It is a super-2 number, since 2×7820661² = 122325476953842, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7820669) 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, 1303441 + ... + 1303446.

It is an arithmetic number, because the mean of its divisors is an integer number (2606888).

Almost surely, 2^7820661 is an apocalyptic number.

It is an amenable number.

7820661 is a deficient number, since it is larger than the sum of its proper divisors (2606891).

7820661 is a wasteful number, since it uses less digits than its factorization.

7820661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2606890.

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

The square root of 7820661 is about 2796.5444748832. The cubic root of 7820661 is about 198.4941996118.

The spelling of 7820661 in words is "seven million, eight hundred twenty thousand, six hundred sixty-one".