7818661643 has 8 divisors (see below), whose sum is σ = 8462412000. Its totient is φ = 7180956288.

The previous prime is 7818661639. The next prime is 7818661673. The reversal of 7818661643 is 3461668187.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 7818661643 - 2² = 7818661639 is a prime.

It is a super-2 number, since 2×7818661643² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 7818661591 and 7818661600.

It is not an unprimeable number, because it can be changed into a prime (7818661673) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1508558 + ... + 1513731.

It is an arithmetic number, because the mean of its divisors is an integer number (1057801500).

Almost surely, 2^7818661643 is an apocalyptic number.

7818661643 is a deficient number, since it is larger than the sum of its proper divisors (643750357).

7818661643 is a wasteful number, since it uses less digits than its factorization.

7818661643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3022501.

The product of its digits is 1161216, while the sum is 50.

The square root of 7818661643 is about 88423.1962948637. The cubic root of 7818661643 is about 1984.7728311370.

The spelling of 7818661643 in words is "seven billion, eight hundred eighteen million, six hundred sixty-one thousand, six hundred forty-three".