21221000004 has 48 divisors (see below), whose sum is σ = 51380904960. Its totient is φ = 6811838880.

The previous prime is 21220999973. The next prime is 21221000027. The reversal of 21221000004 is 40000012212.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 252984 + ... + 326255.

It is an arithmetic number, because the mean of its divisors is an integer number (1070435520).

Almost surely, 2^21221000004 is an apocalyptic number.

It is an amenable number.

21221000004 is an abundant number, since it is smaller than the sum of its proper divisors (30159904956).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21221000004 is a wasteful number, since it uses less digits than its factorization.

21221000004 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 579360 (or 579358 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 12.

Adding to 21221000004 its reverse (40000012212), we get a palindrome (61221012216).

The spelling of 21221000004 in words is "twenty-one billion, two hundred twenty-one million, four", and thus it is an aban number.