21955650865 has 8 divisors (see below), whose sum is σ = 26390622888. Its totient is φ = 17535292800.

The previous prime is 21955650863. The next prime is 21955650901. The reversal of 21955650865 is 56805655912.

It can be written as a sum of positive squares in 4 ways, for example, as 10542360976 + 11413289889 = 102676^2 + 106833^2 .

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

It is not a de Polignac number, because 21955650865 - 2¹ = 21955650863 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21955650863) 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, 3650182 + ... + 3656191.

It is an arithmetic number, because the mean of its divisors is an integer number (3298827861).

Almost surely, 2^21955650865 is an apocalyptic number.

It is an amenable number.

21955650865 is a deficient number, since it is larger than the sum of its proper divisors (4434972023).

21955650865 is an equidigital number, since it uses as much as digits as its factorization.

21955650865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7306979.

The product of its (nonzero) digits is 3240000, while the sum is 52.

The spelling of 21955650865 in words is "twenty-one billion, nine hundred fifty-five million, six hundred fifty thousand, eight hundred sixty-five".