21561655195 has 8 divisors (see below), whose sum is σ = 25879169520. Its totient is φ = 17245868640.

The previous prime is 21561655133. The next prime is 21561655211. The reversal of 21561655195 is 59155616512.

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

It is not a de Polignac number, because 21561655195 - 2⁹ = 21561654683 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 404325 + ... + 454534.

It is an arithmetic number, because the mean of its divisors is an integer number (3234896190).

Almost surely, 2^21561655195 is an apocalyptic number.

21561655195 is a deficient number, since it is larger than the sum of its proper divisors (4317514325).

21561655195 is an equidigital number, since it uses as much as digits as its factorization.

21561655195 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 863885.

The product of its digits is 405000, while the sum is 46.

The spelling of 21561655195 in words is "twenty-one billion, five hundred sixty-one million, six hundred fifty-five thousand, one hundred ninety-five".