21579963819 has 4 divisors (see below), whose sum is σ = 28773285096. Its totient is φ = 14386642544.

The previous prime is 21579963809. The next prime is 21579963851. The reversal of 21579963819 is 91836997512.

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 21579963819 - 2²³ = 21571575211 is a prime.

It is a super-2 number, since 2×21579963819² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21579963809) 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, 3596660634 + ... + 3596660639.

It is an arithmetic number, because the mean of its divisors is an integer number (7193321274).

Almost surely, 2^21579963819 is an apocalyptic number.

21579963819 is a deficient number, since it is larger than the sum of its proper divisors (7193321277).

21579963819 is an equidigital number, since it uses as much as digits as its factorization.

21579963819 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7193321276.

The product of its digits is 7348320, while the sum is 60.

The spelling of 21579963819 in words is "twenty-one billion, five hundred seventy-nine million, nine hundred sixty-three thousand, eight hundred nineteen".