21011841824 has 12 divisors (see below), whose sum is σ = 41367063654. Its totient is φ = 10505920896.

The previous prime is 21011841811. The next prime is 21011841841. The reversal of 21011841824 is 42814811012.

It can be written as a sum of positive squares in only one way, i.e., 18297431824 + 2714410000 = 135268^2 + 52100^2 .

It is a Harshad number since it is a multiple of its sum of digits (32), and also a Moran number because the ratio is a prime number: 656620057 = 21011841824 / (2 + 1 + 0 + 1 + 1 + 8 + 4 + 1 + 8 + 2 + 4).

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 328309997 + ... + 328310060.

Almost surely, 2^21011841824 is an apocalyptic number.

It is an amenable number.

21011841824 is a deficient number, since it is larger than the sum of its proper divisors (20355221830).

21011841824 is an equidigital number, since it uses as much as digits as its factorization.

21011841824 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 656620067 (or 656620059 counting only the distinct ones).

The product of its (nonzero) digits is 4096, while the sum is 32.

The spelling of 21011841824 in words is "twenty-one billion, eleven million, eight hundred forty-one thousand, eight hundred twenty-four".