21365601 has 4 divisors (see below), whose sum is σ = 28487472. Its totient is φ = 14243732.

The previous prime is 21365593. The next prime is 21365609. The reversal of 21365601 is 10656312.

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 an interprime number because it is at equal distance from previous prime (21365593) and next prime (21365609).

It is a cyclic number.

It is not a de Polignac number, because 21365601 - 2³ = 21365593 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21365609) 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, 3560931 + ... + 3560936.

It is an arithmetic number, because the mean of its divisors is an integer number (7121868).

Almost surely, 2^21365601 is an apocalyptic number.

It is an amenable number.

21365601 is a deficient number, since it is larger than the sum of its proper divisors (7121871).

21365601 is an equidigital number, since it uses as much as digits as its factorization.

21365601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7121870.

The product of its (nonzero) digits is 1080, while the sum is 24.

The square root of 21365601 is about 4622.2939110359. The cubic root of 21365601 is about 277.4842714890.

The spelling of 21365601 in words is "twenty-one million, three hundred sixty-five thousand, six hundred one".