21065746851 has 48 divisors (see below), whose sum is σ = 33101033472. Its totient is φ = 12870792000.

The previous prime is 21065746831. The next prime is 21065746859. The reversal of 21065746851 is 15864756012.

21065746851 is a `hidden beast` number, since 2 + 10 + 6 + 574 + 68 + 5 + 1 = 666.

It is not a de Polignac number, because 21065746851 - 2³⁰ = 19992005027 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21065746797 and 21065746806.

It is not an unprimeable number, because it can be changed into a prime (21065746859) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 631866 + ... + 664368.

It is an arithmetic number, because the mean of its divisors is an integer number (689604864).

Almost surely, 2^21065746851 is an apocalyptic number.

21065746851 is a deficient number, since it is larger than the sum of its proper divisors (12035286621).

21065746851 is a wasteful number, since it uses less digits than its factorization.

21065746851 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32664 (or 32661 counting only the distinct ones).

The product of its (nonzero) digits is 403200, while the sum is 45.

The spelling of 21065746851 in words is "twenty-one billion, sixty-five million, seven hundred forty-six thousand, eight hundred fifty-one".