51229890221 has 2 divisors, whose sum is σ = 51229890222. Its totient is φ = 51229890220.

The previous prime is 51229890203. The next prime is 51229890233. The reversal of 51229890221 is 12209892215.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 40345141321 + 10884748900 = 200861^2 + 104330^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51229890221 is a prime.

It is a super-2 number, since 2×51229890221² (a number of 22 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51229890281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25614945110 + 25614945111.

It is an arithmetic number, because the mean of its divisors is an integer number (25614945111).

Almost surely, 2^51229890221 is an apocalyptic number.

It is an amenable number.

51229890221 is a deficient number, since it is larger than the sum of its proper divisors (1).

51229890221 is an equidigital number, since it uses as much as digits as its factorization.

51229890221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 51840, while the sum is 41.

The spelling of 51229890221 in words is "fifty-one billion, two hundred twenty-nine million, eight hundred ninety thousand, two hundred twenty-one".