21373645644305 has 16 divisors (see below), whose sum is σ = 25655863242240. Its totient is φ = 17093924747328.

The previous prime is 21373645644301. The next prime is 21373645644317. The reversal of 21373645644305 is 50344654637312.

It is a cyclic number.

It is not a de Polignac number, because 21373645644305 - 2² = 21373645644301 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21373645644301) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 553143176 + ... + 553181814.

It is an arithmetic number, because the mean of its divisors is an integer number (1603491452640).

Almost surely, 2^{21373645644305} is an apocalyptic number.

It is an amenable number.

21373645644305 is a deficient number, since it is larger than the sum of its proper divisors (4282217597935).

21373645644305 is a wasteful number, since it uses less digits than its factorization.

21373645644305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68080.

The product of its (nonzero) digits is 21772800, while the sum is 53.

The spelling of 21373645644305 in words is "twenty-one trillion, three hundred seventy-three billion, six hundred forty-five million, six hundred forty-four thousand, three hundred five".