21878304051 has 4 divisors (see below), whose sum is σ = 29171072072. Its totient is φ = 14585536032.

The previous prime is 21878304047. The next prime is 21878304059. The reversal of 21878304051 is 15040387812.

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

It is not a de Polignac number, because 21878304051 - 2² = 21878304047 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21878304059) 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, 3646384006 + ... + 3646384011.

It is an arithmetic number, because the mean of its divisors is an integer number (7292768018).

Almost surely, 2^21878304051 is an apocalyptic number.

21878304051 is a deficient number, since it is larger than the sum of its proper divisors (7292768021).

21878304051 is an equidigital number, since it uses as much as digits as its factorization.

21878304051 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7292768020.

The product of its (nonzero) digits is 53760, while the sum is 39.

The spelling of 21878304051 in words is "twenty-one billion, eight hundred seventy-eight million, three hundred four thousand, fifty-one".