21858717611 has 4 divisors (see below), whose sum is σ = 21862639824. Its totient is φ = 21854795400.

The previous prime is 21858717581. The next prime is 21858717619. The reversal of 21858717611 is 11671785812.

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-21858717611 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21858717619) by changing a digit.

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, 1952735 + ... + 1963896.

It is an arithmetic number, because the mean of its divisors is an integer number (5465659956).

Almost surely, 2^21858717611 is an apocalyptic number.

21858717611 is a deficient number, since it is larger than the sum of its proper divisors (3922213).

21858717611 is an equidigital number, since it uses as much as digits as its factorization.

21858717611 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3922212.

The product of its digits is 188160, while the sum is 47.

The spelling of 21858717611 in words is "twenty-one billion, eight hundred fifty-eight million, seven hundred seventeen thousand, six hundred eleven".