21021010001 has 4 divisors (see below), whose sum is σ = 21533717604. Its totient is φ = 20508302400.

The previous prime is 21021009979. The next prime is 21021010013. The reversal of 21021010001 is 10001012012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1421290000 + 19599720001 = 37700^2 + 139999^2 .

It is a cyclic number.

It is not a de Polignac number, because 21021010001 - 2¹⁰ = 21021008977 is a prime.

It is a super-2 number, since 2×21021010001² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21021030001) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 256353740 + ... + 256353821.

It is an arithmetic number, because the mean of its divisors is an integer number (5383429401).

Almost surely, 2^21021010001 is an apocalyptic number.

It is an amenable number.

21021010001 is a deficient number, since it is larger than the sum of its proper divisors (512707603).

21021010001 is an equidigital number, since it uses as much as digits as its factorization.

21021010001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 512707602.

The product of its (nonzero) digits is 4, while the sum is 8.

Adding to 21021010001 its reverse (10001012012), we get a palindrome (31022022013).

The spelling of 21021010001 in words is "twenty-one billion, twenty-one million, ten thousand, one".