8121757986 has 12 divisors (see below), whose sum is σ = 17597142342. Its totient is φ = 2707252656.

The previous prime is 8121757981. The next prime is 8121758011. The reversal of 8121757986 is 6897571218.

It can be written as a sum of positive squares in only one way, i.e., 4248562761 + 3873195225 = 65181^2 + 62235^2 .

It is a super-4 number, since 4×8121757986⁴ (a number of 41 digits) contains 4444 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (8121757981) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 225604371 + ... + 225604406.

Almost surely, 2^8121757986 is an apocalyptic number.

8121757986 is an abundant number, since it is smaller than the sum of its proper divisors (9475384356).

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

8121757986 is a wasteful number, since it uses less digits than its factorization.

8121757986 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 451208785 (or 451208782 counting only the distinct ones).

The product of its digits is 1693440, while the sum is 54.

The square root of 8121757986 is about 90120.7966342952. The cubic root of 8121757986 is about 2010.0954539951.

The spelling of 8121757986 in words is "eight billion, one hundred twenty-one million, seven hundred fifty-seven thousand, nine hundred eighty-six".