51721785 has 12 divisors (see below), whose sum is σ = 89651172. Its totient is φ = 27584928.

The previous prime is 51721771. The next prime is 51721793. The reversal of 51721785 is 58712715.

51721785 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 8003241 + 43718544 = 2829^2 + 6612^2 .

It is not a de Polignac number, because 51721785 - 2⁵ = 51721753 is a prime.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 574642 + ... + 574731.

It is an arithmetic number, because the mean of its divisors is an integer number (7470931).

Almost surely, 2^51721785 is an apocalyptic number.

It is an amenable number.

51721785 is a deficient number, since it is larger than the sum of its proper divisors (37929387).

51721785 is a wasteful number, since it uses less digits than its factorization.

51721785 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1149384 (or 1149381 counting only the distinct ones).

The product of its digits is 19600, while the sum is 36.

The square root of 51721785 is about 7191.7859395285. The cubic root of 51721785 is about 372.5842579243.

The spelling of 51721785 in words is "fifty-one million, seven hundred twenty-one thousand, seven hundred eighty-five".