21969562609 has 8 divisors (see below), whose sum is σ = 21997559880. Its totient is φ = 21941584896.

The previous prime is 21969562561. The next prime is 21969562613. The reversal of 21969562609 is 90626596912.

It can be written as a sum of positive squares in 4 ways, for example, as 16628876209 + 5340686400 = 128953^2 + 73080^2 .

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 21969562609 - 2⁷ = 21969562481 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21969562609.

It is not an unprimeable number, because it can be changed into a prime (21969562669) 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, 4195657 + ... + 4200889.

It is an arithmetic number, because the mean of its divisors is an integer number (2749694985).

Almost surely, 2^21969562609 is an apocalyptic number.

It is an amenable number.

21969562609 is a deficient number, since it is larger than the sum of its proper divisors (27997271).

21969562609 is a wasteful number, since it uses less digits than its factorization.

21969562609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9779.

The product of its (nonzero) digits is 3149280, while the sum is 55.

It can be divided in two parts, 21 and 969562609, that added together give a triangular number (969562630 = T₄₄₀₃₅).

The spelling of 21969562609 in words is "twenty-one billion, nine hundred sixty-nine million, five hundred sixty-two thousand, six hundred nine".