51509965 has 8 divisors (see below), whose sum is σ = 66566808. Its totient is φ = 38038080.

The previous prime is 51509951. The next prime is 51509971. The reversal of 51509965 is 56990515.

It can be written as a sum of positive squares in 4 ways, for example, as 11744329 + 39765636 = 3427^2 + 6306^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 51509965 - 2¹³ = 51501773 is a prime.

It is a Duffinian number.

It is a congruent number.

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, 396166 + ... + 396295.

It is an arithmetic number, because the mean of its divisors is an integer number (8320851).

Almost surely, 2^51509965 is an apocalyptic number.

It is an amenable number.

51509965 is a deficient number, since it is larger than the sum of its proper divisors (15056843).

51509965 is a wasteful number, since it uses less digits than its factorization.

51509965 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 792479.

The product of its (nonzero) digits is 60750, while the sum is 40.

The square root of 51509965 is about 7177.0443080700. The cubic root of 51509965 is about 372.0749381731.

The spelling of 51509965 in words is "fifty-one million, five hundred nine thousand, nine hundred sixty-five".