21439257203205 has 48 divisors (see below), whose sum is σ = 38445165233280. Its totient is φ = 11039307801984.

The previous prime is 21439257203201. The next prime is 21439257203257. The reversal of 21439257203205 is 50230275293412.

21439257203205 is a `hidden beast` number, since 2 + 1 + 4 + 392 + 57 + 2 + 0 + 3 + 205 = 666.

It is not a de Polignac number, because 21439257203205 - 2² = 21439257203201 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21439257203201) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 21124114 + ... + 22115756.

It is an arithmetic number, because the mean of its divisors is an integer number (800940942360).

Almost surely, 2^{21439257203205} is an apocalyptic number.

It is an amenable number.

21439257203205 is a deficient number, since it is larger than the sum of its proper divisors (17005908030075).

21439257203205 is a wasteful number, since it uses less digits than its factorization.

21439257203205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1008250 (or 1008247 counting only the distinct ones).

The product of its (nonzero) digits is 907200, while the sum is 45.

The spelling of 21439257203205 in words is "twenty-one trillion, four hundred thirty-nine billion, two hundred fifty-seven million, two hundred three thousand, two hundred five".