21021200001 has 8 divisors (see below), whose sum is σ = 31142518560. Its totient is φ = 14014133316.

The previous prime is 21021199973. The next prime is 21021200023. The reversal of 21021200001 is 10000212012.

It is not a de Polignac number, because 21021200001 - 2⁶ = 21021199937 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is not an unprimeable number, because it can be changed into a prime (21021200041) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 389281455 + ... + 389281508.

It is an arithmetic number, because the mean of its divisors is an integer number (3892814820).

Almost surely, 2^21021200001 is an apocalyptic number.

It is an amenable number.

21021200001 is a deficient number, since it is larger than the sum of its proper divisors (10121318559).

21021200001 is an equidigital number, since it uses as much as digits as its factorization.

21021200001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 778562972 (or 778562966 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

Adding to 21021200001 its reverse (10000212012), we get a palindrome (31021412013).

The spelling of 21021200001 in words is "twenty-one billion, twenty-one million, two hundred thousand, one".