21326601 has 16 divisors (see below), whose sum is σ = 29494080. Its totient is φ = 13697280.

The previous prime is 21326593. The next prime is 21326609. The reversal of 21326601 is 10662312.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21326593) and next prime (21326609).

It is not a de Polignac number, because 21326601 - 2³ = 21326593 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21326609) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9165 + ... + 11253.

It is an arithmetic number, because the mean of its divisors is an integer number (1843380).

Almost surely, 2^21326601 is an apocalyptic number.

It is an amenable number.

21326601 is a deficient number, since it is larger than the sum of its proper divisors (8167479).

21326601 is a wasteful number, since it uses less digits than its factorization.

21326601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2216.

The product of its (nonzero) digits is 432, while the sum is 21.

The square root of 21326601 is about 4618.0732995482. The cubic root of 21326601 is about 277.3153320506.

Adding to 21326601 its reverse (10662312), we get a palindrome (31988913).

The spelling of 21326601 in words is "twenty-one million, three hundred twenty-six thousand, six hundred one".