20219999 has 4 divisors (see below), whose sum is σ = 20447280. Its totient is φ = 19992720.

The previous prime is 20219951. The next prime is 20220007. The reversal of 20219999 is 99991202.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20219999 is a prime.

It is a Duffinian number.

20219999 is a modest number, since divided by 9999 gives 2021 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20219939) 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, 113507 + ... + 113684.

It is an arithmetic number, because the mean of its divisors is an integer number (5111820).

Almost surely, 2^20219999 is an apocalyptic number.

20219999 is a deficient number, since it is larger than the sum of its proper divisors (227281).

20219999 is an equidigital number, since it uses as much as digits as its factorization.

20219999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 227280.

The product of its (nonzero) digits is 26244, while the sum is 41.

The square root of 20219999 is about 4496.6653199899. The cubic root of 20219999 is about 272.4334163836.

The spelling of 20219999 in words is "twenty million, two hundred nineteen thousand, nine hundred ninety-nine".