811493640 has 224 divisors, whose sum is σ = 2900341080. Its totient is φ = 203544576.

The previous prime is 811493597. The next prime is 811493647. The reversal of 811493640 is 46394118.

811493640 is a `hidden beast` number, since 8 + 1 + 1 + 4 + 9 + 3 + 640 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 536663556 + 274830084 = 23166^2 + 16578^2 .

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

It is a junction number, because it is equal to n+sod(n) for n = 811493595 and 811493604.

It is not an unprimeable number, because it can be changed into a prime (811493647) by changing a digit.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 494902 + ... + 496538.

Almost surely, 2^811493640 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 811493640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1450170540).

811493640 is an abundant number, since it is smaller than the sum of its proper divisors (2088847440).

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

811493640 is a wasteful number, since it uses less digits than its factorization.

811493640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1683 (or 1664 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 36.

The square root of 811493640 is about 28486.7274357726. The cubic root of 811493640 is about 932.7423736328.

The spelling of 811493640 in words is "eight hundred eleven million, four hundred ninety-three thousand, six hundred forty".