21927234809 has 2 divisors, whose sum is σ = 21927234810. Its totient is φ = 21927234808.

The previous prime is 21927234781. The next prime is 21927234821. The reversal of 21927234809 is 90843272912.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11194274809 + 10732960000 = 105803^2 + 103600^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21927234809 is a prime.

It is not a weakly prime, because it can be changed into another prime (21927234869) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10963617404 + 10963617405.

It is an arithmetic number, because the mean of its divisors is an integer number (10963617405).

Almost surely, 2^21927234809 is an apocalyptic number.

It is an amenable number.

21927234809 is a deficient number, since it is larger than the sum of its proper divisors (1).

21927234809 is an equidigital number, since it uses as much as digits as its factorization.

21927234809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 435456, while the sum is 47.

The spelling of 21927234809 in words is "twenty-one billion, nine hundred twenty-seven million, two hundred thirty-four thousand, eight hundred nine".