13640799821 has 4 divisors (see below), whose sum is σ = 14880872544. Its totient is φ = 12400727100.

The previous prime is 13640799787. The next prime is 13640799841. The reversal of 13640799821 is 12899704631.

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 13640799821 - 2¹⁴ = 13640783437 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 13640799821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13640799841) 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, 620036345 + ... + 620036366.

It is an arithmetic number, because the mean of its divisors is an integer number (3720218136).

Almost surely, 2^13640799821 is an apocalyptic number.

13640799821 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

13640799821 is a deficient number, since it is larger than the sum of its proper divisors (1240072723).

13640799821 is a wasteful number, since it uses less digits than its factorization.

13640799821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1240072722.

The product of its (nonzero) digits is 653184, while the sum is 50.

The spelling of 13640799821 in words is "thirteen billion, six hundred forty million, seven hundred ninety-nine thousand, eight hundred twenty-one".