51721285 has 16 divisors (see below), whose sum is σ = 77380992. Its totient is φ = 32241600.

The previous prime is 51721261. The next prime is 51721309. The reversal of 51721285 is 58212715.

It is an interprime number because it is at equal distance from previous prime (51721261) and next prime (51721309).

It is not a de Polignac number, because 51721285 - 2¹¹ = 51719237 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 66786 + ... + 67555.

It is an arithmetic number, because the mean of its divisors is an integer number (4836312).

Almost surely, 2^51721285 is an apocalyptic number.

51721285 is a gapful number since it is divisible by the number (55) formed by its first and last digit.

It is an amenable number.

51721285 is a deficient number, since it is larger than the sum of its proper divisors (25659707).

51721285 is a wasteful number, since it uses less digits than its factorization.

51721285 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 134364.

The product of its digits is 5600, while the sum is 31.

The square root of 51721285 is about 7191.7511775645. The cubic root of 51721285 is about 372.5830573165.

The spelling of 51721285 in words is "fifty-one million, seven hundred twenty-one thousand, two hundred eighty-five".