21546893845 has 4 divisors (see below), whose sum is σ = 25856272620. Its totient is φ = 17237515072.

The previous prime is 21546893843. The next prime is 21546893857. The reversal of 21546893845 is 54839864512.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 13217411089 + 8329482756 = 114967^2 + 91266^2 .

It is a cyclic number.

It is not a de Polignac number, because 21546893845 - 2¹ = 21546893843 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21546893843) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2154689380 + ... + 2154689389.

It is an arithmetic number, because the mean of its divisors is an integer number (6464068155).

Almost surely, 2^21546893845 is an apocalyptic number.

It is an amenable number.

21546893845 is a deficient number, since it is larger than the sum of its proper divisors (4309378775).

21546893845 is an equidigital number, since it uses as much as digits as its factorization.

21546893845 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4309378774.

The product of its digits is 8294400, while the sum is 55.

The spelling of 21546893845 in words is "twenty-one billion, five hundred forty-six million, eight hundred ninety-three thousand, eight hundred forty-five".