21660424009361 has 4 divisors (see below), whose sum is σ = 21661100739300. Its totient is φ = 21659747279424.

The previous prime is 21660424009313. The next prime is 21660424009409. The reversal of 21660424009361 is 16390042406612.

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

It is an interprime number because it is at equal distance from previous prime (21660424009313) and next prime (21660424009409).

It can be written as a sum of positive squares in 2 ways, for example, as 8209456996225 + 13450967013136 = 2865215^2 + 3667556^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21660424009361 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21660424008361) 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, 338316956 + ... + 338380973.

It is an arithmetic number, because the mean of its divisors is an integer number (5415275184825).

Almost surely, 2^{21660424009361} is an apocalyptic number.

It is an amenable number.

21660424009361 is a deficient number, since it is larger than the sum of its proper divisors (676729939).

21660424009361 is an equidigital number, since it uses as much as digits as its factorization.

21660424009361 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 676729938.

The product of its (nonzero) digits is 373248, while the sum is 44.

The spelling of 21660424009361 in words is "twenty-one trillion, six hundred sixty billion, four hundred twenty-four million, nine thousand, three hundred sixty-one".