815845970787904 has 448 divisors, whose sum is σ = 2079425446871040. Its totient is φ = 309153972879360.

The previous prime is 815845970787901. The next prime is 815845970787929. The reversal of 815845970787904 is 409787079548518.

It is a tau number, because it is divible by the number of its divisors (448).

It is not an unprimeable number, because it can be changed into a prime (815845970787901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 41771838619 + ... + 41771858149.

Almost surely, 2^{815845970787904} 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 815845970787904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1039712723435520).

815845970787904 is an abundant number, since it is smaller than the sum of its proper divisors (1263579476083136).

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

815845970787904 is a wasteful number, since it uses less digits than its factorization.

815845970787904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21986 (or 21976 counting only the distinct ones).

The product of its (nonzero) digits is 5689958400, while the sum is 82.

The spelling of 815845970787904 in words is "eight hundred fifteen trillion, eight hundred forty-five billion, nine hundred seventy million, seven hundred eighty-seven thousand, nine hundred four".