21364873693 has 4 divisors (see below), whose sum is σ = 21366191968. Its totient is φ = 21363555420.

The previous prime is 21364873669. The next prime is 21364873723. The reversal of 21364873693 is 39637846312.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21364873693 - 2⁹ = 21364873181 is a prime.

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 21364873693.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21364873633) 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, 634521 + ... + 667342.

It is an arithmetic number, because the mean of its divisors is an integer number (5341547992).

Almost surely, 2^21364873693 is an apocalyptic number.

It is an amenable number.

21364873693 is a deficient number, since it is larger than the sum of its proper divisors (1318275).

21364873693 is a wasteful number, since it uses less digits than its factorization.

21364873693 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1318274.

The product of its digits is 3919104, while the sum is 52.

The spelling of 21364873693 in words is "twenty-one billion, three hundred sixty-four million, eight hundred seventy-three thousand, six hundred ninety-three".