21013001 has 4 divisors (see below), whose sum is σ = 21027600. Its totient is φ = 20998404.

The previous prime is 21012997. The next prime is 21013019. The reversal of 21013001 is 10031012.

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 21013001 - 2² = 21012997 is a prime.

It is a super-2 number, since 2×21013001² = 883092422052002, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21013001.

It is not an unprimeable number, because it can be changed into a prime (21013021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4871 + ... + 8108.

It is an arithmetic number, because the mean of its divisors is an integer number (5256900).

Almost surely, 2^21013001 is an apocalyptic number.

It is an amenable number.

21013001 is a deficient number, since it is larger than the sum of its proper divisors (14599).

21013001 is a wasteful number, since it uses less digits than its factorization.

21013001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14598.

The product of its (nonzero) digits is 6, while the sum is 8.

The square root of 21013001 is about 4583.9940008687. The cubic root of 21013001 is about 275.9493404535.

Adding to 21013001 its reverse (10031012), we get a palindrome (31044013).

The spelling of 21013001 in words is "twenty-one million, thirteen thousand, one".