21612640673573 has 4 divisors (see below), whose sum is σ = 21810921780780. Its totient is φ = 21414359566368.

The previous prime is 21612640673551. The next prime is 21612640673597. The reversal of 21612640673573 is 37537604621612.

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 14573817799489 + 7038822874084 = 3817567^2 + 2653078^2 .

It is a cyclic number.

It is not a de Polignac number, because 21612640673573 - 2⁸ = 21612640673317 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21612640673513) 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, 99140553440 + ... + 99140553657.

It is an arithmetic number, because the mean of its divisors is an integer number (5452730445195).

Almost surely, 2^{21612640673573} is an apocalyptic number.

It is an amenable number.

21612640673573 is a deficient number, since it is larger than the sum of its proper divisors (198281107207).

21612640673573 is a wasteful number, since it uses less digits than its factorization.

21612640673573 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 198281107206.

The product of its (nonzero) digits is 7620480, while the sum is 53.

The spelling of 21612640673573 in words is "twenty-one trillion, six hundred twelve billion, six hundred forty million, six hundred seventy-three thousand, five hundred seventy-three".