21247461695 has 4 divisors (see below), whose sum is σ = 25496954040. Its totient is φ = 16997969352.

The previous prime is 21247461667. The next prime is 21247461727. The reversal of 21247461695 is 59616474212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21247461695 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2124746165 + ... + 2124746174.

It is an arithmetic number, because the mean of its divisors is an integer number (6374238510).

Almost surely, 2^21247461695 is an apocalyptic number.

21247461695 is a deficient number, since it is larger than the sum of its proper divisors (4249492345).

21247461695 is an equidigital number, since it uses as much as digits as its factorization.

21247461695 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4249492344.

The product of its digits is 725760, while the sum is 47.

The spelling of 21247461695 in words is "twenty-one billion, two hundred forty-seven million, four hundred sixty-one thousand, six hundred ninety-five".