21601630404617 has 4 divisors (see below), whose sum is σ = 21611051091780. Its totient is φ = 21592209717456.

The previous prime is 21601630404611. The next prime is 21601630404647. The reversal of 21601630404617 is 71640403610612.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 5083022757136 + 16518607647481 = 2254556^2 + 4064309^2 .

It is a cyclic number.

It is not a de Polignac number, because 21601630404617 - 2⁶ = 21601630404553 is a prime.

It is a super-2 number, since 2×21601630404617² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21601630404611) 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, 4710340142 + ... + 4710344727.

It is an arithmetic number, because the mean of its divisors is an integer number (5402762772945).

Almost surely, 2^{21601630404617} is an apocalyptic number.

It is an amenable number.

21601630404617 is a deficient number, since it is larger than the sum of its proper divisors (9420687163).

21601630404617 is an equidigital number, since it uses as much as digits as its factorization.

21601630404617 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9420687162.

The product of its (nonzero) digits is 145152, while the sum is 41.

The spelling of 21601630404617 in words is "twenty-one trillion, six hundred one billion, six hundred thirty million, four hundred four thousand, six hundred seventeen".