21858646646 has 16 divisors (see below), whose sum is σ = 32894769600. Its totient is φ = 10893747720.

The previous prime is 21858646633. The next prime is 21858646657. The reversal of 21858646646 is 64664685812.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21858646591 and 21858646600.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2835305 + ... + 2843003.

It is an arithmetic number, because the mean of its divisors is an integer number (2055923100).

Almost surely, 2^21858646646 is an apocalyptic number.

21858646646 is a deficient number, since it is larger than the sum of its proper divisors (11036122954).

21858646646 is a wasteful number, since it uses less digits than its factorization.

21858646646 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12139.

The product of its digits is 13271040, while the sum is 56.

The spelling of 21858646646 in words is "twenty-one billion, eight hundred fifty-eight million, six hundred forty-six thousand, six hundred forty-six".