81035594640 has 1800 divisors, whose sum is σ = 392617710144. Its totient is φ = 15041894400.

The previous prime is 81035594603. The next prime is 81035594641. The reversal of 81035594640 is 4649553018.

81035594640 is a `hidden beast` number, since 8 + 10 + 3 + 5 + 594 + 6 + 40 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (81035594641) by changing a digit.

It is a polite number, since it can be written in 359 ways as a sum of consecutive naturals, for example, 2614051425 + ... + 2614051455.

Almost surely, 2^81035594640 is an apocalyptic number.

81035594640 is a gapful number since it is divisible by the number (80) 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 81035594640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (196308855072).

81035594640 is an abundant number, since it is smaller than the sum of its proper divisors (311582115504).

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

81035594640 is a wasteful number, since it uses less digits than its factorization.

81035594640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 131 (or 72 counting only the distinct ones).

The product of its (nonzero) digits is 518400, while the sum is 45.

The spelling of 81035594640 in words is "eighty-one billion, thirty-five million, five hundred ninety-four thousand, six hundred forty".