5618851681 has 3 divisors (see below), whose sum is σ = 5618926641. Its totient is φ = 5618776722.

The previous prime is 5618851669. The next prime is 5618851691. The reversal of 5618851681 is 1861588165.

The square root of 5618851681 is 74959.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 5618851681 - 2²¹ = 5616754529 is a prime.

It is a super-2 number, since 2×5618851681² = 63142988426153051522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (5618851691) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 37480 + ... + 112438.

It is an arithmetic number, because the mean of its divisors is an integer number (1872975547).

Almost surely, 2^5618851681 is an apocalyptic number.

5618851681 is the 74959-th square number.

5618851681 is the 37480-th centered octagonal number.

It is an amenable number.

5618851681 is a deficient number, since it is larger than the sum of its proper divisors (74960).

5618851681 is an frugal number, since it uses more digits than its factorization.

5618851681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 149918 (or 74959 counting only the distinct ones).

The product of its digits is 460800, while the sum is 49.

The cubic root of 5618851681 is about 1777.7984481753.

Multiplying 5618851681 by its sum of digits (49), we get a square (275323732369 = 524713²).

The spelling of 5618851681 in words is "five billion, six hundred eighteen million, eight hundred fifty-one thousand, six hundred eighty-one".