818561856 has 168 divisors, whose sum is σ = 2539325376. Its totient is φ = 232028160.

The previous prime is 818561837. The next prime is 818561957. The reversal of 818561856 is 658165818.

It is a tau number, because it is divible by the number of its divisors (168).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is an alternating number because its digits alternate between even and odd.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1570876 + ... + 1571396.

It is an arithmetic number, because the mean of its divisors is an integer number (15115032).

Almost surely, 2^818561856 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 818561856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1269662688).

818561856 is an abundant number, since it is smaller than the sum of its proper divisors (1720763520).

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

818561856 is a wasteful number, since it uses less digits than its factorization.

818561856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 717 (or 700 counting only the distinct ones).

The product of its digits is 460800, while the sum is 48.

The square root of 818561856 is about 28610.5200232362. The cubic root of 818561856 is about 935.4426516058.

The spelling of 818561856 in words is "eight hundred eighteen million, five hundred sixty-one thousand, eight hundred fifty-six".