51245521 has 2 divisors, whose sum is σ = 51245522. Its totient is φ = 51245520.

The previous prime is 51245507. The next prime is 51245533. The reversal of 51245521 is 12554215.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 42771600 + 8473921 = 6540^2 + 2911^2 .

It is a cyclic number.

It is not a de Polignac number, because 51245521 - 2⁷ = 51245393 is a prime.

It is a super-2 number, since 2×51245521² = 5252206845122882, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (51245501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25622760 + 25622761.

It is an arithmetic number, because the mean of its divisors is an integer number (25622761).

Almost surely, 2^51245521 is an apocalyptic number.

It is an amenable number.

51245521 is a deficient number, since it is larger than the sum of its proper divisors (1).

51245521 is an equidigital number, since it uses as much as digits as its factorization.

51245521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2000, while the sum is 25.

The square root of 51245521 is about 7158.5976978735. The cubic root of 51245521 is about 371.4371208443.

Adding to 51245521 its reverse (12554215), we get a palindrome (63799736).

The spelling of 51245521 in words is "fifty-one million, two hundred forty-five thousand, five hundred twenty-one".