21655120648619 has 2 divisors, whose sum is σ = 21655120648620. Its totient is φ = 21655120648618.

The previous prime is 21655120648571. The next prime is 21655120648633. The reversal of 21655120648619 is 91684602155612.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21655120648619 - 2⁸ = 21655120648363 is a prime.

It is a super-2 number, since 2×21655120648619² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21655120648649) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10827560324309 + 10827560324310.

It is an arithmetic number, because the mean of its divisors is an integer number (10827560324310).

Almost surely, 2^{21655120648619} is an apocalyptic number.

21655120648619 is a deficient number, since it is larger than the sum of its proper divisors (1).

21655120648619 is an equidigital number, since it uses as much as digits as its factorization.

21655120648619 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6220800, while the sum is 56.

The spelling of 21655120648619 in words is "twenty-one trillion, six hundred fifty-five billion, one hundred twenty million, six hundred forty-eight thousand, six hundred nineteen".