21252581723 has 2 divisors, whose sum is σ = 21252581724. Its totient is φ = 21252581722.

The previous prime is 21252581687. The next prime is 21252581783. The reversal of 21252581723 is 32718525212.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21252581723 is a prime.

It is not a weakly prime, because it can be changed into another prime (21252581783) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10626290861 + 10626290862.

It is an arithmetic number, because the mean of its divisors is an integer number (10626290862).

Almost surely, 2^21252581723 is an apocalyptic number.

21252581723 is a deficient number, since it is larger than the sum of its proper divisors (1).

21252581723 is an equidigital number, since it uses as much as digits as its factorization.

21252581723 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 67200, while the sum is 38.

The spelling of 21252581723 in words is "twenty-one billion, two hundred fifty-two million, five hundred eighty-one thousand, seven hundred twenty-three".