7866516138 has 64 divisors (see below), whose sum is σ = 17319899520. Its totient is φ = 2367090432.

The previous prime is 7866516109. The next prime is 7866516139. The reversal of 7866516138 is 8316156687.

It is a super-2 number, since 2×7866516138² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (7866516139) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 902256 + ... + 910932.

It is an arithmetic number, because the mean of its divisors is an integer number (270623430).

Almost surely, 2^7866516138 is an apocalyptic number.

7866516138 is a gapful number since it is divisible by the number (78) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 7866516138, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (8659949760).

7866516138 is an abundant number, since it is smaller than the sum of its proper divisors (9453383382).

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

7866516138 is a wasteful number, since it uses less digits than its factorization.

7866516138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8951.

The product of its digits is 1451520, while the sum is 51.

The square root of 7866516138 is about 88693.3827182164. The cubic root of 7866516138 is about 1988.8138970255.

The spelling of 7866516138 in words is "seven billion, eight hundred sixty-six million, five hundred sixteen thousand, one hundred thirty-eight".