21204928601 has 4 divisors (see below), whose sum is σ = 21231535332. Its totient is φ = 21178321872.

The previous prime is 21204928583. The next prime is 21204928603. The reversal of 21204928601 is 10682940212.

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

It can be written as a sum of positive squares in 2 ways, for example, as 11810472976 + 9394455625 = 108676^2 + 96925^2 .

It is a cyclic number.

It is not a de Polignac number, because 21204928601 - 2²² = 21200734297 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21204928603) 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 3 ways as a sum of consecutive naturals, for example, 13302170 + ... + 13303763.

It is an arithmetic number, because the mean of its divisors is an integer number (5307883833).

Almost surely, 2^21204928601 is an apocalyptic number.

It is an amenable number.

21204928601 is a deficient number, since it is larger than the sum of its proper divisors (26606731).

21204928601 is an equidigital number, since it uses as much as digits as its factorization.

21204928601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26606730.

The product of its (nonzero) digits is 13824, while the sum is 35.

The spelling of 21204928601 in words is "twenty-one billion, two hundred four million, nine hundred twenty-eight thousand, six hundred one".