13621661 has 4 divisors (see below), whose sum is σ = 13989852. Its totient is φ = 13253472.

The previous prime is 13621649. The next prime is 13621667. The reversal of 13621661 is 16612631.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 11689561 + 1932100 = 3419^2 + 1390^2 .

It is a cyclic number.

It is not a de Polignac number, because 13621661 - 2²² = 9427357 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 13621661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13621667) 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, 184040 + ... + 184113.

It is an arithmetic number, because the mean of its divisors is an integer number (3497463).

Almost surely, 2^13621661 is an apocalyptic number.

It is an amenable number.

13621661 is a deficient number, since it is larger than the sum of its proper divisors (368191).

13621661 is an equidigital number, since it uses as much as digits as its factorization.

13621661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 368190.

The product of its digits is 1296, while the sum is 26.

The square root of 13621661 is about 3690.7534461137. The cubic root of 13621661 is about 238.8232968488.

The spelling of 13621661 in words is "thirteen million, six hundred twenty-one thousand, six hundred sixty-one".