51173898221 has 4 divisors (see below), whose sum is σ = 51174457500. Its totient is φ = 51173338944.

The previous prime is 51173898211. The next prime is 51173898233. The reversal of 51173898221 is 12289837115.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 23528185321 + 27645712900 = 153389^2 + 166270^2 .

It is a cyclic number.

It is not a de Polignac number, because 51173898221 - 2⁶ = 51173898157 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 (51173898211) 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, 106766 + ... + 337263.

It is an arithmetic number, because the mean of its divisors is an integer number (12793614375).

Almost surely, 2^51173898221 is an apocalyptic number.

It is an amenable number.

51173898221 is a deficient number, since it is larger than the sum of its proper divisors (559279).

51173898221 is a wasteful number, since it uses less digits than its factorization.

51173898221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 559278.

The product of its digits is 241920, while the sum is 47.

The spelling of 51173898221 in words is "fifty-one billion, one hundred seventy-three million, eight hundred ninety-eight thousand, two hundred twenty-one".