13621591 has 4 divisors (see below), whose sum is σ = 13629352. Its totient is φ = 13613832.

The previous prime is 13621577. The next prime is 13621603. The reversal of 13621591 is 19512631.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 13621591 - 2⁷ = 13621463 is a prime.

It is a pancake number, because a pancake can be divided into 13621591 parts by 5219 straight cuts.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13621541) 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, 145 + ... + 5221.

It is an arithmetic number, because the mean of its divisors is an integer number (3407338).

Almost surely, 2^13621591 is an apocalyptic number.

13621591 is a deficient number, since it is larger than the sum of its proper divisors (7761).

13621591 is an equidigital number, since it uses as much as digits as its factorization.

13621591 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7760.

The product of its digits is 1620, while the sum is 28.

The square root of 13621591 is about 3690.7439629430. The cubic root of 13621591 is about 238.8228877539.

The spelling of 13621591 in words is "thirteen million, six hundred twenty-one thousand, five hundred ninety-one".