21000221204 has 12 divisors (see below), whose sum is σ = 36816370164. Its totient is φ = 10481258304.

The previous prime is 21000221189. The next prime is 21000221243. The reversal of 21000221204 is 40212200012.

It can be written as a sum of positive squares in 2 ways, for example, as 11374649104 + 9625572100 = 106652^2 + 98110^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4710569 + ... + 4715024.

It is an arithmetic number, because the mean of its divisors is an integer number (3068030847).

Almost surely, 2^21000221204 is an apocalyptic number.

It is an amenable number.

21000221204 is a deficient number, since it is larger than the sum of its proper divisors (15816148960).

21000221204 is a wasteful number, since it uses less digits than its factorization.

21000221204 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9426154 (or 9426152 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 14.

Adding to 21000221204 its reverse (40212200012), we get a palindrome (61212421216).

The spelling of 21000221204 in words is "twenty-one billion, two hundred twenty-one thousand, two hundred four".