51550221001 has 2 divisors, whose sum is σ = 51550221002. Its totient is φ = 51550221000.

The previous prime is 51550220999. The next prime is 51550221017. The reversal of 51550221001 is 10012205515.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 44590657225 + 6959563776 = 211165^2 + 83424^2 .

It is a cyclic number.

It is not a de Polignac number, because 51550221001 - 2¹ = 51550220999 is a prime.

Together with 51550220999, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (51550221061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25775110500 + 25775110501.

It is an arithmetic number, because the mean of its divisors is an integer number (25775110501).

Almost surely, 2^51550221001 is an apocalyptic number.

It is an amenable number.

51550221001 is a deficient number, since it is larger than the sum of its proper divisors (1).

51550221001 is an equidigital number, since it uses as much as digits as its factorization.

51550221001 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 500, while the sum is 22.

Adding to 51550221001 its reverse (10012205515), we get a palindrome (61562426516).

The spelling of 51550221001 in words is "fifty-one billion, five hundred fifty million, two hundred twenty-one thousand, one".