51391605 has 16 divisors (see below), whose sum is σ = 82387584. Its totient is φ = 27355200.

The previous prime is 51391601. The next prime is 51391619. The reversal of 51391605 is 50619315.

It is not a de Polignac number, because 51391605 - 2² = 51391601 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51391601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5280 + ... + 11430.

It is an arithmetic number, because the mean of its divisors is an integer number (5149224).

Almost surely, 2^51391605 is an apocalyptic number.

It is an amenable number.

51391605 is a deficient number, since it is larger than the sum of its proper divisors (30995979).

51391605 is a wasteful number, since it uses less digits than its factorization.

51391605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6716.

The product of its (nonzero) digits is 4050, while the sum is 30.

The square root of 51391605 is about 7168.7938316010. The cubic root of 51391605 is about 371.7897340467.

The spelling of 51391605 in words is "fifty-one million, three hundred ninety-one thousand, six hundred five".