21907349923 has 4 divisors (see below), whose sum is σ = 23060368360. Its totient is φ = 20754331488.

The previous prime is 21907349903. The next prime is 21907349929. The reversal of 21907349923 is 32994370912.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21907349923 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21907349929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 576509190 + ... + 576509227.

It is an arithmetic number, because the mean of its divisors is an integer number (5765092090).

Almost surely, 2^21907349923 is an apocalyptic number.

21907349923 is a deficient number, since it is larger than the sum of its proper divisors (1153018437).

21907349923 is a wasteful number, since it uses less digits than its factorization.

21907349923 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1153018436.

The product of its (nonzero) digits is 734832, while the sum is 49.

The spelling of 21907349923 in words is "twenty-one billion, nine hundred seven million, three hundred forty-nine thousand, nine hundred twenty-three".