815755680 has 216 divisors, whose sum is σ = 2861785836. Its totient is φ = 211599360.

The previous prime is 815755649. The next prime is 815755691. The reversal of 815755680 is 86557518.

815755680 is a `hidden beast` number, since 8 + 15 + 7 + 556 + 80 = 666.

It can be written as a sum of positive squares in 6 ways, for example, as 767376 + 814988304 = 876^2 + 28548^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 2420472 + ... + 2420808.

Almost surely, 2^815755680 is an apocalyptic number.

815755680 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 815755680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1430892918).

815755680 is an abundant number, since it is smaller than the sum of its proper divisors (2046030156).

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

815755680 is a wasteful number, since it uses less digits than its factorization.

815755680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 440 (or 388 counting only the distinct ones).

The product of its (nonzero) digits is 336000, while the sum is 45.

The square root of 815755680 is about 28561.4369386416. The cubic root of 815755680 is about 934.3724730155.

The spelling of 815755680 in words is "eight hundred fifteen million, seven hundred fifty-five thousand, six hundred eighty".