21504642345 has 16 divisors (see below), whose sum is σ = 38230475520. Its totient is φ = 11469142512.

The previous prime is 21504642331. The next prime is 21504642347. The reversal of 21504642345 is 54324640512.

21504642345 is a `hidden beast` number, since 2 + 1 + 5 + 0 + 4 + 642 + 3 + 4 + 5 = 666.

It is not a de Polignac number, because 21504642345 - 2⁷ = 21504642217 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21504642347) 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, 79646689 + ... + 79646958.

It is an arithmetic number, because the mean of its divisors is an integer number (2389404720).

Almost surely, 2^21504642345 is an apocalyptic number.

It is an amenable number.

21504642345 is a deficient number, since it is larger than the sum of its proper divisors (16725833175).

21504642345 is a wasteful number, since it uses less digits than its factorization.

21504642345 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 159293661 (or 159293655 counting only the distinct ones).

The product of its (nonzero) digits is 115200, while the sum is 36.

The spelling of 21504642345 in words is "twenty-one billion, five hundred four million, six hundred forty-two thousand, three hundred forty-five".