8921205647 has 4 divisors (see below), whose sum is σ = 8921462616. Its totient is φ = 8920948680.

The previous prime is 8921205613. The next prime is 8921205659. The reversal of 8921205647 is 7465021298.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 8921205647 - 2¹² = 8921201551 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 8921205598 and 8921205607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8921205677) 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, 66413 + ... + 149174.

It is an arithmetic number, because the mean of its divisors is an integer number (2230365654).

Almost surely, 2^8921205647 is an apocalyptic number.

8921205647 is a deficient number, since it is larger than the sum of its proper divisors (256969).

8921205647 is a wasteful number, since it uses less digits than its factorization.

8921205647 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 256968.

The product of its (nonzero) digits is 241920, while the sum is 44.

The square root of 8921205647 is about 94452.1341579956. The cubic root of 8921205647 is about 2073.9956931748.

The spelling of 8921205647 in words is "eight billion, nine hundred twenty-one million, two hundred five thousand, six hundred forty-seven".