21308601 has 4 divisors (see below), whose sum is σ = 28411472. Its totient is φ = 14205732.

The previous prime is 21308579. The next prime is 21308611. The reversal of 21308601 is 10680312.

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 not a de Polignac number, because 21308601 - 2¹⁵ = 21275833 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21308611) 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 3 ways as a sum of consecutive naturals, for example, 3551431 + ... + 3551436.

It is an arithmetic number, because the mean of its divisors is an integer number (7102868).

Almost surely, 2^21308601 is an apocalyptic number.

It is an amenable number.

21308601 is a deficient number, since it is larger than the sum of its proper divisors (7102871).

21308601 is an equidigital number, since it uses as much as digits as its factorization.

21308601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7102870.

The product of its (nonzero) digits is 288, while the sum is 21.

The square root of 21308601 is about 4616.1240234638. The cubic root of 21308601 is about 277.2372905320.

Adding to 21308601 its reverse (10680312), we get a palindrome (31988913).

It can be divided in two parts, 2130 and 8601, that added together give a triangular number (10731 = T₁₄₆).

The spelling of 21308601 in words is "twenty-one million, three hundred eight thousand, six hundred one".