21218365657393 has 8 divisors (see below), whose sum is σ = 22274063458560. Its totient is φ = 20185870005840.

The previous prime is 21218365657337. The next prime is 21218365657421. The reversal of 21218365657393 is 39375656381212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21218365657393 - 2¹⁷ = 21218365526321 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21218365657303) 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 7 ways as a sum of consecutive naturals, for example, 5800535530 + ... + 5800539187.

It is an arithmetic number, because the mean of its divisors is an integer number (2784257932320).

Almost surely, 2^{21218365657393} is an apocalyptic number.

It is an amenable number.

21218365657393 is a deficient number, since it is larger than the sum of its proper divisors (1055697801167).

21218365657393 is a wasteful number, since it uses less digits than its factorization.

21218365657393 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11601074807.

The product of its digits is 48988800, while the sum is 61.

The spelling of 21218365657393 in words is "twenty-one trillion, two hundred eighteen billion, three hundred sixty-five million, six hundred fifty-seven thousand, three hundred ninety-three".