51721893 has 24 divisors (see below), whose sum is σ = 77395968. Its totient is φ = 33257952.

The previous prime is 51721861. The next prime is 51721897. The reversal of 51721893 is 39812715.

51721893 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 51721893 - 2⁵ = 51721861 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51721897) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 41680 + ... + 42902.

It is an arithmetic number, because the mean of its divisors is an integer number (3224832).

Almost surely, 2^51721893 is an apocalyptic number.

It is an amenable number.

51721893 is a deficient number, since it is larger than the sum of its proper divisors (25674075).

51721893 is a wasteful number, since it uses less digits than its factorization.

51721893 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1393 (or 1390 counting only the distinct ones).

The product of its digits is 15120, while the sum is 36.

The square root of 51721893 is about 7191.7934480907. The cubic root of 51721893 is about 372.5845172546.

The spelling of 51721893 in words is "fifty-one million, seven hundred twenty-one thousand, eight hundred ninety-three".