51646565 has 16 divisors (see below), whose sum is σ = 63309936. Its totient is φ = 40435200.

The previous prime is 51646559. The next prime is 51646571. The reversal of 51646565 is 56564615.

It is an interprime number because it is at equal distance from previous prime (51646559) and next prime (51646571).

It can be written as a sum of positive squares in 8 ways, for example, as 25411681 + 26234884 = 5041^2 + 5122^2 .

It is not a de Polignac number, because 51646565 - 2⁴ = 51646549 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 15 ways as a sum of consecutive naturals, for example, 95195 + ... + 95735.

It is an arithmetic number, because the mean of its divisors is an integer number (3956871).

Almost surely, 2^51646565 is an apocalyptic number.

It is an amenable number.

51646565 is a deficient number, since it is larger than the sum of its proper divisors (11663371).

51646565 is a wasteful number, since it uses less digits than its factorization.

51646565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 920.

The product of its digits is 108000, while the sum is 38.

The square root of 51646565 is about 7186.5544595446. The cubic root of 51646565 is about 372.4035514450.

The spelling of 51646565 in words is "fifty-one million, six hundred forty-six thousand, five hundred sixty-five".