21653560001 has 4 divisors (see below), whose sum is σ = 21653990100. Its totient is φ = 21653129904.

The previous prime is 21653559997. The next prime is 21653560043. The reversal of 21653560001 is 10006535612.

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 7430612401 + 14222947600 = 86201^2 + 119260^2 .

It is a cyclic number.

It is not a de Polignac number, because 21653560001 - 2² = 21653559997 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21653565001) 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, 127706 + ... + 244163.

It is an arithmetic number, because the mean of its divisors is an integer number (5413497525).

Almost surely, 2^21653560001 is an apocalyptic number.

It is an amenable number.

21653560001 is a deficient number, since it is larger than the sum of its proper divisors (430099).

21653560001 is an equidigital number, since it uses as much as digits as its factorization.

21653560001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 430098.

The product of its (nonzero) digits is 5400, while the sum is 29.

The spelling of 21653560001 in words is "twenty-one billion, six hundred fifty-three million, five hundred sixty thousand, one".