20591819 has 4 divisors (see below), whose sum is σ = 20696544. Its totient is φ = 20487096.

The previous prime is 20591807. The next prime is 20591833. The reversal of 20591819 is 91819502.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 91819502 = 2 ⋅45909751.

It is a cyclic number.

It is not a de Polignac number, because 20591819 - 2⁴ = 20591803 is a prime.

It is a super-2 number, since 2×20591819² = 848046019457522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20591119) 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 3 ways as a sum of consecutive naturals, for example, 52067 + ... + 52460.

It is an arithmetic number, because the mean of its divisors is an integer number (5174136).

Almost surely, 2^20591819 is an apocalyptic number.

20591819 is a deficient number, since it is larger than the sum of its proper divisors (104725).

20591819 is a wasteful number, since it uses less digits than its factorization.

20591819 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 104724.

The product of its (nonzero) digits is 6480, while the sum is 35.

The square root of 20591819 is about 4537.8209528363. The cubic root of 20591819 is about 274.0931849566.

The spelling of 20591819 in words is "twenty million, five hundred ninety-one thousand, eight hundred nineteen".