51643240 has 32 divisors (see below), whose sum is σ = 126761760. Its totient is φ = 18779200.

The previous prime is 51643237. The next prime is 51643261. The reversal of 51643240 is 4234615.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 58246 + ... + 59125.

It is an arithmetic number, because the mean of its divisors is an integer number (3961305).

Almost surely, 2^51643240 is an apocalyptic number.

It is an amenable number.

51643240 is an abundant number, since it is smaller than the sum of its proper divisors (75118520).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

51643240 is a wasteful number, since it uses less digits than its factorization.

51643240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 117393 (or 117389 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 25.

The square root of 51643240 is about 7186.3231210404. The cubic root of 51643240 is about 372.3955595073.

Adding to 51643240 its reverse (4234615), we get a palindrome (55877855).

The spelling of 51643240 in words is "fifty-one million, six hundred forty-three thousand, two hundred forty".