21001221201000 has 256 divisors, whose sum is σ = 71253243509760. Its totient is φ = 5128437657600.

The previous prime is 21001221200941. The next prime is 21001221201001. The reversal of 21001221201000 is 10212210012.

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

It is not an unprimeable number, because it can be changed into a prime (21001221201001) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 3677712 + ... + 7451711.

It is an arithmetic number, because the mean of its divisors is an integer number (278332982460).

Almost surely, 2^{21001221201000} is an apocalyptic number.

21001221201000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21001221201000 is an abundant number, since it is smaller than the sum of its proper divisors (50252022308760).

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

21001221201000 is a wasteful number, since it uses less digits than its factorization.

21001221201000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11129501 (or 11129487 counting only the distinct ones).

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

Adding to 21001221201000 its reverse (10212210012), we get a palindrome (21011433411012).

The spelling of 21001221201000 in words is "twenty-one trillion, one billion, two hundred twenty-one million, two hundred one thousand".