996661 has 4 divisors (see below), whose sum is σ = 1003500. Its totient is φ = 989824.

The previous prime is 996649. The next prime is 996689. The reversal of 996661 is 166699.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 166699 = 13 ⋅12823.

It can be written as a sum of positive squares in 2 ways, for example, as 463761 + 532900 = 681^2 + 730^2 .

It is a cyclic number.

It is not a de Polignac number, because 996661 - 2⁵ = 996629 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 10.

It is a self number, because there is not a number n which added to its sum of digits gives 996661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (996601) 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, 3196 + ... + 3493.

It is an arithmetic number, because the mean of its divisors is an integer number (250875).

2⁹⁹⁶⁶⁶¹ is an apocalyptic number.

It is an amenable number.

996661 is a deficient number, since it is larger than the sum of its proper divisors (6839).

996661 is a wasteful number, since it uses less digits than its factorization.

996661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6838.

The product of its digits is 17496, while the sum is 37.

The square root of 996661 is about 998.3291040534. The cubic root of 996661 is about 99.8885758928. Note that the first 3 decimals are identical.

The spelling of 996661 in words is "nine hundred ninety-six thousand, six hundred sixty-one".