21393881065 has 8 divisors (see below), whose sum is σ = 25740397440. Its totient is φ = 17069944752.

The previous prime is 21393881051. The next prime is 21393881077. The reversal of 21393881065 is 56018839312.

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

It is a cyclic number.

It is not a de Polignac number, because 21393881065 - 2²¹ = 21391783913 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5642929 + ... + 5646718.

It is an arithmetic number, because the mean of its divisors is an integer number (3217549680).

Almost surely, 2^21393881065 is an apocalyptic number.

It is an amenable number.

21393881065 is a deficient number, since it is larger than the sum of its proper divisors (4346516375).

21393881065 is a wasteful number, since it uses less digits than its factorization.

21393881065 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11290031.

The product of its (nonzero) digits is 311040, while the sum is 46.

The spelling of 21393881065 in words is "twenty-one billion, three hundred ninety-three million, eight hundred eighty-one thousand, sixty-five".