21039194455 has 16 divisors (see below), whose sum is σ = 26348690880. Its totient is φ = 16097137408.

The previous prime is 21039194453. The next prime is 21039194479. The reversal of 21039194455 is 55449193012.

It is a cyclic number.

It is not a de Polignac number, because 21039194455 - 2¹ = 21039194453 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21039194453) 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, 1288281 + ... + 1304509.

It is an arithmetic number, because the mean of its divisors is an integer number (1646793180).

Almost surely, 2^21039194455 is an apocalyptic number.

21039194455 is a deficient number, since it is larger than the sum of its proper divisors (5309496425).

21039194455 is a wasteful number, since it uses less digits than its factorization.

21039194455 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27530.

The product of its (nonzero) digits is 194400, while the sum is 43.

The spelling of 21039194455 in words is "twenty-one billion, thirty-nine million, one hundred ninety-four thousand, four hundred fifty-five".