51777721 has 2 divisors, whose sum is σ = 51777722. Its totient is φ = 51777720.

The previous prime is 51777703. The next prime is 51777743. The reversal of 51777721 is 12777715.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 51194025 + 583696 = 7155^2 + 764^2 .

It is a cyclic number.

It is not a de Polignac number, because 51777721 - 2¹⁷ = 51646649 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (51727721) 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, 25888860 + 25888861.

It is an arithmetic number, because the mean of its divisors is an integer number (25888861).

Almost surely, 2^51777721 is an apocalyptic number.

It is an amenable number.

51777721 is a deficient number, since it is larger than the sum of its proper divisors (1).

51777721 is an equidigital number, since it uses as much as digits as its factorization.

51777721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 24010, while the sum is 37.

The square root of 51777721 is about 7195.6737697036. The cubic root of 51777721 is about 372.7185234926.

The spelling of 51777721 in words is "fifty-one million, seven hundred seventy-seven thousand, seven hundred twenty-one".