51132721 has 2 divisors, whose sum is σ = 51132722. Its totient is φ = 51132720.

The previous prime is 51132707. The next prime is 51132751. The reversal of 51132721 is 12723115.

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., 49280400 + 1852321 = 7020^2 + 1361^2 .

It is a cyclic number.

It is not a de Polignac number, because 51132721 - 2⁵ = 51132689 is a prime.

It is a super-2 number, since 2×51132721² = 5229110313727682, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 51132692 and 51132701.

It is not a weakly prime, because it can be changed into another prime (51132751) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25566360 + 25566361.

It is an arithmetic number, because the mean of its divisors is an integer number (25566361).

Almost surely, 2^51132721 is an apocalyptic number.

It is an amenable number.

51132721 is a deficient number, since it is larger than the sum of its proper divisors (1).

51132721 is an equidigital number, since it uses as much as digits as its factorization.

51132721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 420, while the sum is 22.

The square root of 51132721 is about 7150.7147195228. The cubic root of 51132721 is about 371.1643888042.

Adding to 51132721 its reverse (12723115), we get a palindrome (63855836).

The spelling of 51132721 in words is "fifty-one million, one hundred thirty-two thousand, seven hundred twenty-one".