20215447 has 4 divisors (see below), whose sum is σ = 23103376. Its totient is φ = 17327520.

The previous prime is 20215417. The next prime is 20215451. The reversal of 20215447 is 74451202.

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

It is not a de Polignac number, because 20215447 - 2⁷ = 20215319 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20215417) 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, 1443954 + ... + 1443967.

It is an arithmetic number, because the mean of its divisors is an integer number (5775844).

Almost surely, 2^20215447 is an apocalyptic number.

20215447 is a deficient number, since it is larger than the sum of its proper divisors (2887929).

20215447 is an equidigital number, since it uses as much as digits as its factorization.

20215447 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2887928.

The product of its (nonzero) digits is 2240, while the sum is 25.

The square root of 20215447 is about 4496.1591386427. The cubic root of 20215447 is about 272.4129711142.

Adding to 20215447 its reverse (74451202), we get a palindrome (94666649).

The spelling of 20215447 in words is "twenty million, two hundred fifteen thousand, four hundred forty-seven".