21450545609 has 2 divisors, whose sum is σ = 21450545610. Its totient is φ = 21450545608.

The previous prime is 21450545579. The next prime is 21450545639. The reversal of 21450545609 is 90654505412.

It is a balanced prime because it is at equal distance from previous prime (21450545579) and next prime (21450545639).

It can be written as a sum of positive squares in only one way, i.e., 19321000000 + 2129545609 = 139000^2 + 46147^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21450545609 is a prime.

It is not a weakly prime, because it can be changed into another prime (21450545639) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10725272804 + 10725272805.

It is an arithmetic number, because the mean of its divisors is an integer number (10725272805).

Almost surely, 2^21450545609 is an apocalyptic number.

It is an amenable number.

21450545609 is a deficient number, since it is larger than the sum of its proper divisors (1).

21450545609 is an equidigital number, since it uses as much as digits as its factorization.

21450545609 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 216000, while the sum is 41.

The spelling of 21450545609 in words is "twenty-one billion, four hundred fifty million, five hundred forty-five thousand, six hundred nine".