396581840 has 40 divisors (see below), whose sum is σ = 925688520. Its totient is φ = 158007296.

The previous prime is 396581753. The next prime is 396581849. The reversal of 396581840 is 48185693.

It can be written as a sum of positive squares in 4 ways, for example, as 185286544 + 211295296 = 13612^2 + 14536^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a junction number, because it is equal to n+sod(n) for n = 396581791 and 396581800.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (396581849) 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, 10916 + ... + 30204.

It is an arithmetic number, because the mean of its divisors is an integer number (23142213).

Almost surely, 2^396581840 is an apocalyptic number.

It is an amenable number.

396581840 is an abundant number, since it is smaller than the sum of its proper divisors (529106680).

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

396581840 is a wasteful number, since it uses less digits than its factorization.

396581840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19559 (or 19553 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 44.

The square root of 396581840 is about 19914.3626561334. The cubic root of 396581840 is about 734.7015247281.

The spelling of 396581840 in words is "three hundred ninety-six million, five hundred eighty-one thousand, eight hundred forty".