21064443399 has 12 divisors (see below), whose sum is σ = 30710778696. Its totient is φ = 13911718992.

The previous prime is 21064443391. The next prime is 21064443403. The reversal of 21064443399 is 99334446012.

21064443399 is a `hidden beast` number, since 210 + 6 + 4 + 4 + 43 + 399 = 666.

It is not a de Polignac number, because 21064443399 - 2³ = 21064443391 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21064443391) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 10935924 + ... + 10937849.

It is an arithmetic number, because the mean of its divisors is an integer number (2559231558).

Almost surely, 2^21064443399 is an apocalyptic number.

21064443399 is a deficient number, since it is larger than the sum of its proper divisors (9646335297).

21064443399 is a wasteful number, since it uses less digits than its factorization.

21064443399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21873886 (or 21873883 counting only the distinct ones).

The product of its (nonzero) digits is 559872, while the sum is 45.

The spelling of 21064443399 in words is "twenty-one billion, sixty-four million, four hundred forty-three thousand, three hundred ninety-nine".