51091385 has 4 divisors (see below), whose sum is σ = 61309668. Its totient is φ = 40873104.

The previous prime is 51091357. The next prime is 51091393. The reversal of 51091385 is 58319015.

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

It can be written as a sum of positive squares in 2 ways, for example, as 39175081 + 11916304 = 6259^2 + 3452^2 .

It is a cyclic number.

It is not a de Polignac number, because 51091385 - 2⁶ = 51091321 is a prime.

It is a super-2 number, since 2×51091385² = 5220659242436450, which contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5109134 + ... + 5109143.

It is an arithmetic number, because the mean of its divisors is an integer number (15327417).

Almost surely, 2^51091385 is an apocalyptic number.

It is an amenable number.

51091385 is a deficient number, since it is larger than the sum of its proper divisors (10218283).

51091385 is a wasteful number, since it uses less digits than its factorization.

51091385 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10218282.

The product of its (nonzero) digits is 5400, while the sum is 32.

The square root of 51091385 is about 7147.8237946944. The cubic root of 51091385 is about 371.0643446639.

The spelling of 51091385 in words is "fifty-one million, ninety-one thousand, three hundred eighty-five".