9780661 has 16 divisors (see below), whose sum is σ = 11397888. Its totient is φ = 8294400.

The previous prime is 9780647. The next prime is 9780721. The reversal of 9780661 is 1660879.

9780661 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a 6-Lehmer number, since φ(9780661) divides (9780661-1)⁶.

It is a cyclic number.

It is not a de Polignac number, because 9780661 - 2⁹ = 9780149 is a prime.

It is a super-2 number, since 2×9780661² = 191322659193842, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 9780661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9780601) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 35956 + ... + 36226.

It is an arithmetic number, because the mean of its divisors is an integer number (712368).

Almost surely, 2^9780661 is an apocalyptic number.

It is an amenable number.

9780661 is a deficient number, since it is larger than the sum of its proper divisors (1617227).

9780661 is a wasteful number, since it uses less digits than its factorization.

9780661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 492.

The product of its (nonzero) digits is 18144, while the sum is 37.

The square root of 9780661 is about 3127.4048346832. The cubic root of 9780661 is about 213.8566381938.

The spelling of 9780661 in words is "nine million, seven hundred eighty thousand, six hundred sixty-one".