445640 has 32 divisors (see below), whose sum is σ = 1081080. Its totient is φ = 164352.

The previous prime is 445633. The next prime is 445649. The reversal of 445640 is 46544.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 376996 + 68644 = 614^2 + 262^2 .

It is not an unprimeable number, because it can be changed into a prime (445649) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 92 + ... + 948.

2⁴⁴⁵⁶⁴⁰ is an apocalyptic number.

445640 is a gapful number since it is divisible by the number (40) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 445640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (540540).

445640 is an abundant number, since it is smaller than the sum of its proper divisors (635440).

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

445640 is a wasteful number, since it uses less digits than its factorization.

445640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 881 (or 877 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 23.

The square root of 445640 is about 667.5627311347. The cubic root of 445640 is about 76.3826500445.

It can be divided in two parts, 44 and 5640, that multiplied together give a triangular number (248160 = T₇₀₄).

The spelling of 445640 in words is "four hundred forty-five thousand, six hundred forty".