8118721556 has 48 divisors (see below), whose sum is σ = 15898565760. Its totient is φ = 3596400000.

The previous prime is 8118721543. The next prime is 8118721573. The reversal of 8118721556 is 6551278118.

It is a super-2 number, since 2×8118721556² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (44).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 278681 + ... + 306431.

It is an arithmetic number, because the mean of its divisors is an integer number (331220120).

Almost surely, 2^8118721556 is an apocalyptic number.

It is an amenable number.

8118721556 is a deficient number, since it is larger than the sum of its proper divisors (7779844204).

8118721556 is a wasteful number, since it uses less digits than its factorization.

8118721556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27936 (or 27934 counting only the distinct ones).

The product of its digits is 134400, while the sum is 44.

The square root of 8118721556 is about 90103.9486149192. The cubic root of 8118721556 is about 2009.8449222369.

The spelling of 8118721556 in words is "eight billion, one hundred eighteen million, seven hundred twenty-one thousand, five hundred fifty-six".