21306001 has 4 divisors (see below), whose sum is σ = 21332592. Its totient is φ = 21279412.

The previous prime is 21305989. The next prime is 21306023. The reversal of 21306001 is 10060312.

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 21306001 - 2¹⁷ = 21174929 is a prime.

It is a super-2 number, since 2×21306001² = 907891357224002, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21306091) 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, 12055 + ... + 13708.

It is an arithmetic number, because the mean of its divisors is an integer number (5333148).

Almost surely, 2^21306001 is an apocalyptic number.

It is an amenable number.

21306001 is a deficient number, since it is larger than the sum of its proper divisors (26591).

21306001 is an equidigital number, since it uses as much as digits as its factorization.

21306001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26590.

The product of its (nonzero) digits is 36, while the sum is 13.

The square root of 21306001 is about 4615.8423933232. The cubic root of 21306001 is about 277.2260142360.

Adding to 21306001 its reverse (10060312), we get a palindrome (31366313).

The spelling of 21306001 in words is "twenty-one million, three hundred six thousand, one".