21006259639 has 8 divisors (see below), whose sum is σ = 21764921040. Its totient is φ = 20257646976.

The previous prime is 21006259607. The next prime is 21006259709. The reversal of 21006259639 is 93695260012.

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 21006259639 - 2⁵ = 21006259607 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21006259595 and 21006259604.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21006259739) 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, 2507929 + ... + 2516290.

It is an arithmetic number, because the mean of its divisors is an integer number (2720615130).

Almost surely, 2^21006259639 is an apocalyptic number.

21006259639 is a deficient number, since it is larger than the sum of its proper divisors (758661401).

21006259639 is a wasteful number, since it uses less digits than its factorization.

21006259639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5024369.

The product of its (nonzero) digits is 174960, while the sum is 43.

The spelling of 21006259639 in words is "twenty-one billion, six million, two hundred fifty-nine thousand, six hundred thirty-nine".