21001010001 has 4 divisors (see below), whose sum is σ = 28001346672. Its totient is φ = 14000673332.

The previous prime is 21001009999. The next prime is 21001010029. The reversal of 21001010001 is 10001010012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21001010001 - 2¹ = 21001009999 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21001010071) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3500168331 + ... + 3500168336.

It is an arithmetic number, because the mean of its divisors is an integer number (7000336668).

Almost surely, 2^21001010001 is an apocalyptic number.

It is an amenable number.

21001010001 is a deficient number, since it is larger than the sum of its proper divisors (7000336671).

21001010001 is an equidigital number, since it uses as much as digits as its factorization.

21001010001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7000336670.

The product of its (nonzero) digits is 2, while the sum is 6.

Adding to 21001010001 its reverse (10001010012), we get a palindrome (31002020013).

It can be divided in two parts, 2100 and 1010001, that added together give a palindrome (1012101).

The spelling of 21001010001 in words is "twenty-one billion, one million, ten thousand, one".