21774578545 has 8 divisors (see below), whose sum is σ = 26141003496. Its totient is φ = 17411990016.

The previous prime is 21774578533. The next prime is 21774578563. The reversal of 21774578545 is 54587547712.

It can be written as a sum of positive squares in 4 ways, for example, as 1507924224 + 20266654321 = 38832^2 + 142361^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21774578545 is a prime.

It is a Duffinian number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 946602 + ... + 969331.

It is an arithmetic number, because the mean of its divisors is an integer number (3267625437).

Almost surely, 2^21774578545 is an apocalyptic number.

It is an amenable number.

21774578545 is a deficient number, since it is larger than the sum of its proper divisors (4366424951).

21774578545 is a wasteful number, since it uses less digits than its factorization.

21774578545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1918211.

The product of its digits is 10976000, while the sum is 55.

The spelling of 21774578545 in words is "twenty-one billion, seven hundred seventy-four million, five hundred seventy-eight thousand, five hundred forty-five".