21751664733 has 12 divisors (see below), whose sum is σ = 31724112160. Its totient is φ = 14360321736.

The previous prime is 21751664731. The next prime is 21751664749. The reversal of 21751664733 is 33746615712.

21751664733 is a `hidden beast` number, since 2 + 1 + 7 + 516 + 64 + 73 + 3 = 666.

It is not a de Polignac number, because 21751664733 - 2¹ = 21751664731 is a prime.

It is a super-2 number, since 2×21751664733² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21751664731) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 11731363 + ... + 11733216.

Almost surely, 2^21751664733 is an apocalyptic number.

It is an amenable number.

21751664733 is a deficient number, since it is larger than the sum of its proper divisors (9972447427).

21751664733 is a wasteful number, since it uses less digits than its factorization.

21751664733 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23464688 (or 23464685 counting only the distinct ones).

The product of its digits is 635040, while the sum is 45.

The spelling of 21751664733 in words is "twenty-one billion, seven hundred fifty-one million, six hundred sixty-four thousand, seven hundred thirty-three".