21001221000012 has 24 divisors (see below), whose sum is σ = 53457653454912. Its totient is φ = 6364006363600.

The previous prime is 21001220999987. The next prime is 21001221000031. The reversal of 21001221000012 is 21000012210012.

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

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 79550079414 + ... + 79550079677.

It is an arithmetic number, because the mean of its divisors is an integer number (2227402227288).

Almost surely, 2^{21001221000012} is an apocalyptic number.

21001221000012 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21001221000012 is an abundant number, since it is smaller than the sum of its proper divisors (32456432454900).

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

21001221000012 is a wasteful number, since it uses less digits than its factorization.

21001221000012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 159100159109 (or 159100159107 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21001221000012 its reverse (21000012210012), we get a palindrome (42001233210024).

It can be divided in two parts, 210012210000 and 12, that added together give a palindrome (210012210012).

The spelling of 21001221000012 in words is "twenty-one trillion, one billion, two hundred twenty-one million, twelve", and thus it is an aban number.