21666124139 has 8 divisors (see below), whose sum is σ = 23653954800. Its totient is φ = 19681324000.

The previous prime is 21666124127. The next prime is 21666124157. The reversal of 21666124139 is 93142166612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21666124139 - 2⁸ = 21666123883 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21666124096 and 21666124105.

It is not an unprimeable number, because it can be changed into a prime (21666124169) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 742664 + ... + 771285.

It is an arithmetic number, because the mean of its divisors is an integer number (2956744350).

Almost surely, 2^21666124139 is an apocalyptic number.

21666124139 is a deficient number, since it is larger than the sum of its proper divisors (1987830661).

21666124139 is a wasteful number, since it uses less digits than its factorization.

21666124139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1515261.

The product of its digits is 93312, while the sum is 41.

The spelling of 21666124139 in words is "twenty-one billion, six hundred sixty-six million, one hundred twenty-four thousand, one hundred thirty-nine".