21613260545 has 4 divisors (see below), whose sum is σ = 25935912660. Its totient is φ = 17290608432.

The previous prime is 21613260541. The next prime is 21613260569. The reversal of 21613260545 is 54506231612.

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 3240000241 + 18373260304 = 56921^2 + 135548^2 .

It is a cyclic number.

It is not a de Polignac number, because 21613260545 - 2² = 21613260541 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21613260541) 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, 2161326050 + ... + 2161326059.

It is an arithmetic number, because the mean of its divisors is an integer number (6483978165).

Almost surely, 2^21613260545 is an apocalyptic number.

It is an amenable number.

21613260545 is a deficient number, since it is larger than the sum of its proper divisors (4322652115).

21613260545 is an equidigital number, since it uses as much as digits as its factorization.

21613260545 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4322652114.

The product of its (nonzero) digits is 43200, while the sum is 35.

The spelling of 21613260545 in words is "twenty-one billion, six hundred thirteen million, two hundred sixty thousand, five hundred forty-five".