21128054915 has 8 divisors (see below), whose sum is σ = 27658544688. Its totient is φ = 15365858080.

The previous prime is 21128054897. The next prime is 21128054917. The reversal of 21128054915 is 51945082112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21128054915 - 2⁸ = 21128054659 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21128054917) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 192073172 + ... + 192073281.

It is an arithmetic number, because the mean of its divisors is an integer number (3457318086).

Almost surely, 2^21128054915 is an apocalyptic number.

21128054915 is a deficient number, since it is larger than the sum of its proper divisors (6530489773).

21128054915 is a wasteful number, since it uses less digits than its factorization.

21128054915 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 384146469.

The product of its (nonzero) digits is 28800, while the sum is 38.

The spelling of 21128054915 in words is "twenty-one billion, one hundred twenty-eight million, fifty-four thousand, nine hundred fifteen".