51440729 has 2 divisors, whose sum is σ = 51440730. Its totient is φ = 51440728.

The previous prime is 51440713. The next prime is 51440731. The reversal of 51440729 is 92704415.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 37393225 + 14047504 = 6115^2 + 3748^2 .

It is a cyclic number.

It is not a de Polignac number, because 51440729 - 2⁴ = 51440713 is a prime.

It is a super-2 number, since 2×51440729² = 5292297200102882, which contains 22 as substring.

Together with 51440731, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 51440695 and 51440704.

It is not a weakly prime, because it can be changed into another prime (51445729) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25720364 + 25720365.

It is an arithmetic number, because the mean of its divisors is an integer number (25720365).

Almost surely, 2^51440729 is an apocalyptic number.

It is an amenable number.

51440729 is a deficient number, since it is larger than the sum of its proper divisors (1).

51440729 is an equidigital number, since it uses as much as digits as its factorization.

51440729 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10080, while the sum is 32.

The square root of 51440729 is about 7172.2192520865. The cubic root of 51440729 is about 371.9081579454.

The spelling of 51440729 in words is "fifty-one million, four hundred forty thousand, seven hundred twenty-nine".