6542215681 has 4 divisors (see below), whose sum is σ = 6542386992. Its totient is φ = 6542044372.

The previous prime is 6542215661. The next prime is 6542215697. The reversal of 6542215681 is 1865122456.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 6542215681 - 2¹³ = 6542207489 is a prime.

It is a super-2 number, since 2×6542215681² = 85601172033444587522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6542215601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 546 + ... + 114388.

It is an arithmetic number, because the mean of its divisors is an integer number (1635596748).

Almost surely, 2^6542215681 is an apocalyptic number.

It is an amenable number.

6542215681 is a deficient number, since it is larger than the sum of its proper divisors (171311).

6542215681 is a wasteful number, since it uses less digits than its factorization.

6542215681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 171310.

The product of its digits is 115200, while the sum is 40.

The square root of 6542215681 is about 80883.9643007191. The cubic root of 6542215681 is about 1870.2871322657.

The spelling of 6542215681 in words is "six billion, five hundred forty-two million, two hundred fifteen thousand, six hundred eighty-one".