21206708427 has 8 divisors (see below), whose sum is σ = 28276976016. Its totient is φ = 14137123232.

The previous prime is 21206708401. The next prime is 21206708437. The reversal of 21206708427 is 72480760212.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21206708427 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21206708437) 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, 93048 + ... + 225989.

It is an arithmetic number, because the mean of its divisors is an integer number (3534622002).

Almost surely, 2^21206708427 is an apocalyptic number.

21206708427 is a deficient number, since it is larger than the sum of its proper divisors (7070267589).

21206708427 is a wasteful number, since it uses less digits than its factorization.

21206708427 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 341197.

The product of its (nonzero) digits is 75264, while the sum is 39.

The spelling of 21206708427 in words is "twenty-one billion, two hundred six million, seven hundred eight thousand, four hundred twenty-seven".