20215491 has 8 divisors (see below), whose sum is σ = 26977104. Its totient is φ = 13465440.

The previous prime is 20215463. The next prime is 20215513. The reversal of 20215491 is 19451202.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20215491 - 2¹¹ = 20213443 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20215451) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2785 + ... + 6941.

It is an arithmetic number, because the mean of its divisors is an integer number (3372138).

Almost surely, 2^20215491 is an apocalyptic number.

20215491 is a deficient number, since it is larger than the sum of its proper divisors (6761613).

20215491 is a wasteful number, since it uses less digits than its factorization.

20215491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5781.

The product of its (nonzero) digits is 720, while the sum is 24.

The square root of 20215491 is about 4496.1640317052. The cubic root of 20215491 is about 272.4131687545.

Adding to 20215491 its reverse (19451202), we get a palindrome (39666693).

It can be divided in two parts, 20215 and 491, that added together give a triangular number (20706 = T₂₀₃).

The spelling of 20215491 in words is "twenty million, two hundred fifteen thousand, four hundred ninety-one".