51550065421 has 4 divisors (see below), whose sum is σ = 51551084572. Its totient is φ = 51549046272.

The previous prime is 51550065401. The next prime is 51550065431. The reversal of 51550065421 is 12456005515.

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 50270572521 + 1279492900 = 224211^2 + 35770^2 .

It is a cyclic number.

It is not a de Polignac number, because 51550065421 - 2⁷ = 51550065293 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 (51550065401) 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, 429510 + ... + 536263.

It is an arithmetic number, because the mean of its divisors is an integer number (12887771143).

Almost surely, 2^51550065421 is an apocalyptic number.

It is an amenable number.

51550065421 is a deficient number, since it is larger than the sum of its proper divisors (1019151).

51550065421 is an equidigital number, since it uses as much as digits as its factorization.

51550065421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1019150.

The product of its (nonzero) digits is 30000, while the sum is 34.

The spelling of 51550065421 in words is "fifty-one billion, five hundred fifty million, sixty-five thousand, four hundred twenty-one".