13620021 has 4 divisors (see below), whose sum is σ = 18160032. Its totient is φ = 9080012.

The previous prime is 13620011. The next prime is 13620023. The reversal of 13620021 is 12002631.

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 13620021 - 2¹⁷ = 13488949 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13620023) 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, 2270001 + ... + 2270006.

It is an arithmetic number, because the mean of its divisors is an integer number (4540008).

Almost surely, 2^13620021 is an apocalyptic number.

It is an amenable number.

13620021 is a deficient number, since it is larger than the sum of its proper divisors (4540011).

13620021 is an equidigital number, since it uses as much as digits as its factorization.

13620021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4540010.

The product of its (nonzero) digits is 72, while the sum is 15.

The square root of 13620021 is about 3690.5312625691. The cubic root of 13620021 is about 238.8137119696.

Adding to 13620021 its reverse (12002631), we get a palindrome (25622652).

The spelling of 13620021 in words is "thirteen million, six hundred twenty thousand, twenty-one".