51590221 has 2 divisors, whose sum is σ = 51590222. Its totient is φ = 51590220.

The previous prime is 51590197. The next prime is 51590243. The reversal of 51590221 is 12209515.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 27678121 + 23912100 = 5261^2 + 4890^2 .

It is a cyclic number.

It is not a de Polignac number, because 51590221 - 2¹⁹ = 51065933 is a prime.

It is equal to p_3090751 and since 51590221 and 3090751 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51590261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25795110 + 25795111.

It is an arithmetic number, because the mean of its divisors is an integer number (25795111).

Almost surely, 2^51590221 is an apocalyptic number.

It is an amenable number.

51590221 is a deficient number, since it is larger than the sum of its proper divisors (1).

51590221 is an equidigital number, since it uses as much as digits as its factorization.

51590221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 900, while the sum is 25.

The square root of 51590221 is about 7182.6332914886. The cubic root of 51590221 is about 372.2680771837.

Adding to 51590221 its reverse (12209515), we get a palindrome (63799736).

The spelling of 51590221 in words is "fifty-one million, five hundred ninety thousand, two hundred twenty-one".