21540136067 has 4 divisors (see below), whose sum is σ = 21553442280. Its totient is φ = 21526829856.

The previous prime is 21540136021. The next prime is 21540136097. The reversal of 21540136067 is 76063104512.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21540136067 - 2⁶ = 21540136003 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21540136097) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6650678 + ... + 6653915.

It is an arithmetic number, because the mean of its divisors is an integer number (5388360570).

Almost surely, 2^21540136067 is an apocalyptic number.

21540136067 is a deficient number, since it is larger than the sum of its proper divisors (13306213).

21540136067 is a wasteful number, since it uses less digits than its factorization.

21540136067 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13306212.

The product of its (nonzero) digits is 30240, while the sum is 35.

The spelling of 21540136067 in words is "twenty-one billion, five hundred forty million, one hundred thirty-six thousand, sixty-seven".