51616560221 has 4 divisors (see below), whose sum is σ = 51642229344. Its totient is φ = 51590891100.

The previous prime is 51616560211. The next prime is 51616560251. The reversal of 51616560221 is 12206561615.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 51616560221 - 2⁶ = 51616560157 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 (51616560211) 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, 12831545 + ... + 12835566.

It is an arithmetic number, because the mean of its divisors is an integer number (12910557336).

Almost surely, 2^51616560221 is an apocalyptic number.

It is an amenable number.

51616560221 is a deficient number, since it is larger than the sum of its proper divisors (25669123).

51616560221 is a wasteful number, since it uses less digits than its factorization.

51616560221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25669122.

The product of its (nonzero) digits is 21600, while the sum is 35.

The spelling of 51616560221 in words is "fifty-one billion, six hundred sixteen million, five hundred sixty thousand, two hundred twenty-one".