7861738666 has 4 divisors (see below), whose sum is σ = 11792608002. Its totient is φ = 3930869332.

The previous prime is 7861738649. The next prime is 7861738667. The reversal of 7861738666 is 6668371687.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 6668371687 = 5717 ⋅1166411.

It can be written as a sum of positive squares in only one way, i.e., 7246946641 + 614792025 = 85129^2 + 24795^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 7861738666.

It is not an unprimeable number, because it can be changed into a prime (7861738667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1965434665 + ... + 1965434668.

Almost surely, 2^7861738666 is an apocalyptic number.

7861738666 is a deficient number, since it is larger than the sum of its proper divisors (3930869336).

7861738666 is a wasteful number, since it uses less digits than its factorization.

7861738666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3930869335.

The product of its digits is 12192768, while the sum is 58.

The square root of 7861738666 is about 88666.4461112545. The cubic root of 7861738666 is about 1988.4112017423.

The spelling of 7861738666 in words is "seven billion, eight hundred sixty-one million, seven hundred thirty-eight thousand, six hundred sixty-six".