21333856747 has 16 divisors (see below), whose sum is σ = 25921658880. Its totient is φ = 17161084512.

The previous prime is 21333856727. The next prime is 21333856759. The reversal of 21333856747 is 74765833312.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21333856747 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21333856747.

It is not an unprimeable number, because it can be changed into a prime (21333856727) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1241547 + ... + 1258612.

It is an arithmetic number, because the mean of its divisors is an integer number (1620103680).

Almost surely, 2^21333856747 is an apocalyptic number.

21333856747 is a deficient number, since it is larger than the sum of its proper divisors (4587802133).

21333856747 is a wasteful number, since it uses less digits than its factorization.

21333856747 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2500242.

The product of its digits is 2540160, while the sum is 49.

The spelling of 21333856747 in words is "twenty-one billion, three hundred thirty-three million, eight hundred fifty-six thousand, seven hundred forty-seven".