21002001001 has 8 divisors (see below), whose sum is σ = 21336778944. Its totient is φ = 20668305840.

The previous prime is 21002000989. The next prime is 21002001043. The reversal of 21002001001 is 10010020012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21002001001 - 2¹⁵ = 21001968233 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21002001091) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 231550 + ... + 309223.

It is an arithmetic number, because the mean of its divisors is an integer number (2667097368).

Almost surely, 2^21002001001 is an apocalyptic number.

It is an amenable number.

21002001001 is a deficient number, since it is larger than the sum of its proper divisors (334777943).

21002001001 is an equidigital number, since it uses as much as digits as its factorization.

21002001001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 541391.

The product of its (nonzero) digits is 4, while the sum is 7.

Adding to 21002001001 its reverse (10010020012), we get a palindrome (31012021013).

The spelling of 21002001001 in words is "twenty-one billion, two million, one thousand, one".