21009836794 has 32 divisors (see below), whose sum is σ = 32513704704. Its totient is φ = 10178196480.

The previous prime is 21009836791. The next prime is 21009836803. The reversal of 21009836794 is 49763890012.

21009836794 is digitally balanced in base 5, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×21009836794² (a number of 21 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (21009836791) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2420907 + ... + 2429569.

It is an arithmetic number, because the mean of its divisors is an integer number (1016053272).

Almost surely, 2^21009836794 is an apocalyptic number.

21009836794 is a deficient number, since it is larger than the sum of its proper divisors (11503867910).

21009836794 is a wasteful number, since it uses less digits than its factorization.

21009836794 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9022.

The product of its (nonzero) digits is 653184, while the sum is 49.

The spelling of 21009836794 in words is "twenty-one billion, nine million, eight hundred thirty-six thousand, seven hundred ninety-four".