21655420603361 has 4 divisors (see below), whose sum is σ = 21960426527424. Its totient is φ = 21350414679300.

The previous prime is 21655420603331. The next prime is 21655420603367. The reversal of 21655420603361 is 16330602455612.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21655420603361 - 2²⁶ = 21655353494497 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21655420603367) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 152502961925 + ... + 152502962066.

It is an arithmetic number, because the mean of its divisors is an integer number (5490106631856).

Almost surely, 2^{21655420603361} is an apocalyptic number.

It is an amenable number.

21655420603361 is a deficient number, since it is larger than the sum of its proper divisors (305005924063).

21655420603361 is an equidigital number, since it uses as much as digits as its factorization.

21655420603361 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 305005924062.

The product of its (nonzero) digits is 777600, while the sum is 44.

The spelling of 21655420603361 in words is "twenty-one trillion, six hundred fifty-five billion, four hundred twenty million, six hundred three thousand, three hundred sixty-one".