815485777920 has 768 divisors, whose sum is σ = 3248240486400. Its totient is φ = 192323911680.

The previous prime is 815485777879. The next prime is 815485777961. The reversal of 815485777920 is 29777584518.

815485777920 is a `hidden beast` number, since 8 + 1 + 54 + 8 + 577 + 7 + 9 + 2 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (815485777879) and next prime (815485777961).

It is a tau number, because it is divible by the number of its divisors (768).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 112523737 + ... + 112530983.

It is an arithmetic number, because the mean of its divisors is an integer number (4229479800).

Almost surely, 2^815485777920 is an apocalyptic number.

815485777920 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 815485777920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1624120243200).

815485777920 is an abundant number, since it is smaller than the sum of its proper divisors (2432754708480).

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

815485777920 is a wasteful number, since it uses less digits than its factorization.

815485777920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7331 (or 7305 counting only the distinct ones).

The product of its (nonzero) digits is 39513600, while the sum is 63.

The spelling of 815485777920 in words is "eight hundred fifteen billion, four hundred eighty-five million, seven hundred seventy-seven thousand, nine hundred twenty".