661896 has 48 divisors (see below), whose sum is σ = 1860300. Its totient is φ = 212352.

The previous prime is 661889. The next prime is 661897. The reversal of 661896 is 698166.

It can be written as a sum of positive squares in 2 ways, for example, as 617796 + 44100 = 786^2 + 210^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is a self number, because there is not a number n which added to its sum of digits gives 661896.

It is not an unprimeable number, because it can be changed into a prime (661897) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1930 + ... + 2246.

2⁶⁶¹⁸⁹⁶ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661896, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (930150).

661896 is an abundant number, since it is smaller than the sum of its proper divisors (1198404).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

661896 is a wasteful number, since it uses less digits than its factorization.

661896 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 358 (or 351 counting only the distinct ones).

The product of its digits is 15552, while the sum is 36.

The square root of 661896 is about 813.5699109480. The cubic root of 661896 is about 87.1491693768.

The spelling of 661896 in words is "six hundred sixty-one thousand, eight hundred ninety-six".