51766391 has 4 divisors (see below), whose sum is σ = 51913392. Its totient is φ = 51619392.

The previous prime is 51766381. The next prime is 51766457. The reversal of 51766391 is 19366715.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19366715 = 5 ⋅3873343.

It is a cyclic number.

It is not a de Polignac number, because 51766391 - 2⁶ = 51766327 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 (51766301) 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, 72971 + ... + 73676.

It is an arithmetic number, because the mean of its divisors is an integer number (12978348).

Almost surely, 2^51766391 is an apocalyptic number.

51766391 is a deficient number, since it is larger than the sum of its proper divisors (147001).

51766391 is a wasteful number, since it uses less digits than its factorization.

51766391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 147000.

The product of its digits is 34020, while the sum is 38.

The square root of 51766391 is about 7194.8864480268. The cubic root of 51766391 is about 372.6913354225.

The spelling of 51766391 in words is "fifty-one million, seven hundred sixty-six thousand, three hundred ninety-one".