51220705 has 4 divisors (see below), whose sum is σ = 61464852. Its totient is φ = 40976560.

The previous prime is 51220703. The next prime is 51220709. The reversal of 51220705 is 50702215.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 6718464 + 44502241 = 2592^2 + 6671^2 .

It is not a de Polignac number, because 51220705 - 2¹ = 51220703 is a prime.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51220703) 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 in 3 ways as a sum of consecutive naturals, for example, 5122066 + ... + 5122075.

It is an arithmetic number, because the mean of its divisors is an integer number (15366213).

Almost surely, 2^51220705 is an apocalyptic number.

It is an amenable number.

51220705 is a deficient number, since it is larger than the sum of its proper divisors (10244147).

51220705 is a wasteful number, since it uses less digits than its factorization.

51220705 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10244146.

The product of its (nonzero) digits is 700, while the sum is 22.

The square root of 51220705 is about 7156.8641876174. The cubic root of 51220705 is about 371.3771541604.

The spelling of 51220705 in words is "fifty-one million, two hundred twenty thousand, seven hundred five".