20638291 has 4 divisors (see below), whose sum is σ = 21535632. Its totient is φ = 19740952.

The previous prime is 20638283. The next prime is 20638301. The reversal of 20638291 is 19283602.

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

It is a cyclic number.

It is not a de Polignac number, because 20638291 - 2³ = 20638283 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20638201) 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, 448636 + ... + 448681.

It is an arithmetic number, because the mean of its divisors is an integer number (5383908).

Almost surely, 2^20638291 is an apocalyptic number.

20638291 is a deficient number, since it is larger than the sum of its proper divisors (897341).

20638291 is an equidigital number, since it uses as much as digits as its factorization.

20638291 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 897340.

The product of its (nonzero) digits is 5184, while the sum is 31.

The square root of 20638291 is about 4542.9385864218. The cubic root of 20638291 is about 274.2992229029.

The spelling of 20638291 in words is "twenty million, six hundred thirty-eight thousand, two hundred ninety-one".