21343646687 has 4 divisors (see below), whose sum is σ = 23283978216. Its totient is φ = 19403315160.

The previous prime is 21343646683. The next prime is 21343646717. The reversal of 21343646687 is 78664634312.

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 21343646687 - 2² = 21343646683 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21343646683) 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, 970165748 + ... + 970165769.

It is an arithmetic number, because the mean of its divisors is an integer number (5820994554).

Almost surely, 2^21343646687 is an apocalyptic number.

21343646687 is a deficient number, since it is larger than the sum of its proper divisors (1940331529).

21343646687 is a wasteful number, since it uses less digits than its factorization.

21343646687 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1940331528.

The product of its digits is 3483648, while the sum is 50.

The spelling of 21343646687 in words is "twenty-one billion, three hundred forty-three million, six hundred forty-six thousand, six hundred eighty-seven".