21000326782 has 4 divisors (see below), whose sum is σ = 31500490176. Its totient is φ = 10500163390.

The previous prime is 21000326777. The next prime is 21000326791. The reversal of 21000326782 is 28762300012.

It is a semiprime because it is the product of two primes.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5250081694 + ... + 5250081697.

It is an arithmetic number, because the mean of its divisors is an integer number (7875122544).

Almost surely, 2^21000326782 is an apocalyptic number.

21000326782 is a deficient number, since it is larger than the sum of its proper divisors (10500163394).

21000326782 is a wasteful number, since it uses less digits than its factorization.

21000326782 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10500163393.

The product of its (nonzero) digits is 8064, while the sum is 31.

Adding to 21000326782 its reverse (28762300012), we get a palindrome (49762626794).

The spelling of 21000326782 in words is "twenty-one billion, three hundred twenty-six thousand, seven hundred eighty-two".