21450416647 has 4 divisors (see below), whose sum is σ = 23400454536. Its totient is φ = 19500378760.

The previous prime is 21450416641. The next prime is 21450416731. The reversal of 21450416647 is 74661405412.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21450416647 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21450416641) 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, 975018928 + ... + 975018949.

It is an arithmetic number, because the mean of its divisors is an integer number (5850113634).

Almost surely, 2^21450416647 is an apocalyptic number.

21450416647 is a deficient number, since it is larger than the sum of its proper divisors (1950037889).

21450416647 is a wasteful number, since it uses less digits than its factorization.

21450416647 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1950037888.

The product of its (nonzero) digits is 161280, while the sum is 40.

The spelling of 21450416647 in words is "twenty-one billion, four hundred fifty million, four hundred sixteen thousand, six hundred forty-seven".