51509863 has 4 divisors (see below), whose sum is σ = 51600960. Its totient is φ = 51418768.

The previous prime is 51509851. The next prime is 51509867. The reversal of 51509863 is 36890515.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 51509863 - 2⁵ = 51509831 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51509867) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 44695 + ... + 45832.

It is an arithmetic number, because the mean of its divisors is an integer number (12900240).

Almost surely, 2^51509863 is an apocalyptic number.

51509863 is a deficient number, since it is larger than the sum of its proper divisors (91097).

51509863 is an equidigital number, since it uses as much as digits as its factorization.

51509863 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91096.

The product of its (nonzero) digits is 32400, while the sum is 37.

The square root of 51509863 is about 7177.0372020772. The cubic root of 51509863 is about 372.0746925787.

The spelling of 51509863 in words is "fifty-one million, five hundred nine thousand, eight hundred sixty-three".