21081022709 has 8 divisors (see below), whose sum is σ = 22494531840. Its totient is φ = 19697911776.

The previous prime is 21081022691. The next prime is 21081022741. The reversal of 21081022709 is 90722018012.

It is a happy number.

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 21081022709 - 2¹² = 21081018613 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21081012709) 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 7 ways as a sum of consecutive naturals, for example, 7598117 + ... + 7600890.

It is an arithmetic number, because the mean of its divisors is an integer number (2811816480).

Almost surely, 2^21081022709 is an apocalyptic number.

It is an amenable number.

21081022709 is a deficient number, since it is larger than the sum of its proper divisors (1413509131).

21081022709 is a wasteful number, since it uses less digits than its factorization.

21081022709 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15199099.

The product of its (nonzero) digits is 4032, while the sum is 32.

The spelling of 21081022709 in words is "twenty-one billion, eighty-one million, twenty-two thousand, seven hundred nine".