21051800393 has 16 divisors (see below), whose sum is σ = 23107908096. Its totient is φ = 19058370240.

The previous prime is 21051800381. The next prime is 21051800431. The reversal of 21051800393 is 39300815012.

It is not a de Polignac number, because 21051800393 - 2¹⁰ = 21051799369 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21051800303) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2591408 + ... + 2599518.

It is an arithmetic number, because the mean of its divisors is an integer number (1444244256).

Almost surely, 2^21051800393 is an apocalyptic number.

It is an amenable number.

21051800393 is a deficient number, since it is larger than the sum of its proper divisors (2056107703).

21051800393 is a wasteful number, since it uses less digits than its factorization.

21051800393 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11944.

The product of its (nonzero) digits is 6480, while the sum is 32.

The spelling of 21051800393 in words is "twenty-one billion, fifty-one million, eight hundred thousand, three hundred ninety-three".