21543272667 has 36 divisors (see below), whose sum is σ = 37177022064. Its totient is φ = 11775186720.

The previous prime is 21543272651. The next prime is 21543272687. The reversal of 21543272667 is 76627234512.

21543272667 is a `hidden beast` number, since 2 + 1 + 543 + 27 + 26 + 67 = 666.

It is not a de Polignac number, because 21543272667 - 2⁴ = 21543272651 is a prime.

It is a super-2 number, since 2×21543272667² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21543272687) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 289884 + ... + 356537.

Almost surely, 2^21543272667 is an apocalyptic number.

21543272667 is a deficient number, since it is larger than the sum of its proper divisors (15633749397).

21543272667 is a wasteful number, since it uses less digits than its factorization.

21543272667 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 646480 (or 646454 counting only the distinct ones).

The product of its digits is 846720, while the sum is 45.

The spelling of 21543272667 in words is "twenty-one billion, five hundred forty-three million, two hundred seventy-two thousand, six hundred sixty-seven".