581820642 has 48 divisors (see below), whose sum is σ = 1367566200. Its totient is φ = 177705216.

The previous prime is 581820611. The next prime is 581820643. The reversal of 581820642 is 246028185.

581820642 is a `hidden beast` number, since 5 + 8 + 1 + 8 + 2 + 0 + 642 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 365995161 + 215825481 = 19131^2 + 14691^2 .

It is a junction number, because it is equal to n+sod(n) for n = 581820597 and 581820606.

It is not an unprimeable number, because it can be changed into a prime (581820643) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 22984 + ... + 41132.

Almost surely, 2^581820642 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 581820642, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (683783100).

581820642 is an abundant number, since it is smaller than the sum of its proper divisors (785745558).

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

581820642 is a wasteful number, since it uses less digits than its factorization.

581820642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18307 (or 18304 counting only the distinct ones).

The product of its (nonzero) digits is 30720, while the sum is 36.

The square root of 581820642 is about 24120.9585630422. The cubic root of 581820642 is about 834.8267856369.

The spelling of 581820642 in words is "five hundred eighty-one million, eight hundred twenty thousand, six hundred forty-two".