21533367667 has 6 divisors (see below), whose sum is σ = 25049019588. Its totient is φ = 18457172244.

The previous prime is 21533367637. The next prime is 21533367677. The reversal of 21533367667 is 76676333512.

It is a happy number.

It is not a de Polignac number, because 21533367667 - 2¹⁹ = 21532843379 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (49), and also a Moran number because the ratio is a prime number: 439456483 = 21533367667 / (2 + 1 + 5 + 3 + 3 + 3 + 6 + 7 + 6 + 6 + 7).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21533367667.

It is not an unprimeable number, because it can be changed into a prime (21533367637) 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 5 ways as a sum of consecutive naturals, for example, 219728193 + ... + 219728290.

It is an arithmetic number, because the mean of its divisors is an integer number (4174836598).

Almost surely, 2^21533367667 is an apocalyptic number.

21533367667 is a deficient number, since it is larger than the sum of its proper divisors (3515651921).

21533367667 is an equidigital number, since it uses as much as digits as its factorization.

21533367667 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 439456497 (or 439456490 counting only the distinct ones).

The product of its digits is 2857680, while the sum is 49.

The spelling of 21533367667 in words is "twenty-one billion, five hundred thirty-three million, three hundred sixty-seven thousand, six hundred sixty-seven".