21338782751 has 16 divisors (see below), whose sum is σ = 26388781440. Its totient is φ = 16964212320.

The previous prime is 21338782739. The next prime is 21338782757. The reversal of 21338782751 is 15728783312.

It is not a de Polignac number, because 21338782751 - 2¹⁰ = 21338781727 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21338782696 and 21338782705.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21338782757) 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, 3924185 + ... + 3929618.

It is an arithmetic number, because the mean of its divisors is an integer number (1649298840).

Almost surely, 2^21338782751 is an apocalyptic number.

21338782751 is a deficient number, since it is larger than the sum of its proper divisors (5049998689).

21338782751 is a wasteful number, since it uses less digits than its factorization.

21338782751 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7853846.

The product of its digits is 564480, while the sum is 47.

The spelling of 21338782751 in words is "twenty-one billion, three hundred thirty-eight million, seven hundred eighty-two thousand, seven hundred fifty-one".