21579059851 has 4 divisors (see below), whose sum is σ = 22038188832. Its totient is φ = 21119930872.

The previous prime is 21579059813. The next prime is 21579059881. The reversal of 21579059851 is 15895097512.

It is a happy number.

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 21579059851 - 2¹⁵ = 21579027083 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21579059881) 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, 229564420 + ... + 229564513.

It is an arithmetic number, because the mean of its divisors is an integer number (5509547208).

Almost surely, 2^21579059851 is an apocalyptic number.

21579059851 is a deficient number, since it is larger than the sum of its proper divisors (459128981).

21579059851 is an equidigital number, since it uses as much as digits as its factorization.

21579059851 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 459128980.

The product of its (nonzero) digits is 1134000, while the sum is 52.

The spelling of 21579059851 in words is "twenty-one billion, five hundred seventy-nine million, fifty-nine thousand, eight hundred fifty-one".