21126275447 has 4 divisors (see below), whose sum is σ = 21131287080. Its totient is φ = 21121263816.

The previous prime is 21126275441. The next prime is 21126275449. The reversal of 21126275447 is 74457262112.

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 21126275447 - 2²² = 21122081143 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21126275441) 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, 2499488 + ... + 2507925.

It is an arithmetic number, because the mean of its divisors is an integer number (5282821770).

Almost surely, 2^21126275447 is an apocalyptic number.

21126275447 is a deficient number, since it is larger than the sum of its proper divisors (5011633).

21126275447 is an equidigital number, since it uses as much as digits as its factorization.

21126275447 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5011632.

The product of its digits is 188160, while the sum is 41.

The spelling of 21126275447 in words is "twenty-one billion, one hundred twenty-six million, two hundred seventy-five thousand, four hundred forty-seven".