21504104723 has 2 divisors, whose sum is σ = 21504104724. Its totient is φ = 21504104722.

The previous prime is 21504104689. The next prime is 21504104747. The reversal of 21504104723 is 32740140512.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21504104723 - 2³⁰ = 20430362899 is a prime.

It is not a weakly prime, because it can be changed into another prime (21504104023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10752052361 + 10752052362.

It is an arithmetic number, because the mean of its divisors is an integer number (10752052362).

Almost surely, 2^21504104723 is an apocalyptic number.

21504104723 is a deficient number, since it is larger than the sum of its proper divisors (1).

21504104723 is an equidigital number, since it uses as much as digits as its factorization.

21504104723 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6720, while the sum is 29.

The spelling of 21504104723 in words is "twenty-one billion, five hundred four million, one hundred four thousand, seven hundred twenty-three".