51959721 has 16 divisors (see below), whose sum is σ = 76616640. Its totient is φ = 31057920.

The previous prime is 51959683. The next prime is 51959749. The reversal of 51959721 is 12795915.

It is not a de Polignac number, because 51959721 - 2¹⁷ = 51828649 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 51959721.

It is not an unprimeable number, because it can be changed into a prime (51959221) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8376 + ... + 13193.

It is an arithmetic number, because the mean of its divisors is an integer number (4788540).

Almost surely, 2^51959721 is an apocalyptic number.

It is an amenable number.

51959721 is a deficient number, since it is larger than the sum of its proper divisors (24656919).

51959721 is a wasteful number, since it uses less digits than its factorization.

51959721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21656.

The product of its digits is 28350, while the sum is 39.

The square root of 51959721 is about 7208.3091637360. The cubic root of 51959721 is about 373.1547178281.

The spelling of 51959721 in words is "fifty-one million, nine hundred fifty-nine thousand, seven hundred twenty-one".