20516819 has 4 divisors (see below), whose sum is σ = 20529960. Its totient is φ = 20503680.

The previous prime is 20516803. The next prime is 20516831. The reversal of 20516819 is 91861502.

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 20516819 - 2⁴ = 20516803 is a prime.

It is a super-2 number, since 2×20516819² = 841879723757522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20516849) 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, 3854 + ... + 7475.

It is an arithmetic number, because the mean of its divisors is an integer number (5132490).

Almost surely, 2^20516819 is an apocalyptic number.

20516819 is a deficient number, since it is larger than the sum of its proper divisors (13141).

20516819 is a wasteful number, since it uses less digits than its factorization.

20516819 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13140.

The product of its (nonzero) digits is 4320, while the sum is 32.

The square root of 20516819 is about 4529.5495361018. The cubic root of 20516819 is about 273.7600106151.

The spelling of 20516819 in words is "twenty million, five hundred sixteen thousand, eight hundred nineteen".