21652406543641 has 4 divisors (see below), whose sum is σ = 21949014852532. Its totient is φ = 21355798234752.

The previous prime is 21652406543639. The next prime is 21652406543671. The reversal of 21652406543641 is 14634560425612.

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 15894542345616 + 5757864198025 = 3986796^2 + 2399555^2 .

It is a cyclic number.

It is not a de Polignac number, because 21652406543641 - 2¹ = 21652406543639 is a prime.

It is a super-2 number, since 2×21652406543641² (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 (21652406543671) 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, 148304154336 + ... + 148304154481.

It is an arithmetic number, because the mean of its divisors is an integer number (5487253713133).

Almost surely, 2^{21652406543641} is an apocalyptic number.

It is an amenable number.

21652406543641 is a deficient number, since it is larger than the sum of its proper divisors (296608308891).

21652406543641 is an equidigital number, since it uses as much as digits as its factorization.

21652406543641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 296608308890.

The product of its (nonzero) digits is 4147200, while the sum is 49.

The spelling of 21652406543641 in words is "twenty-one trillion, six hundred fifty-two billion, four hundred six million, five hundred forty-three thousand, six hundred forty-one".