51123791 has 4 divisors (see below), whose sum is σ = 51171000. Its totient is φ = 51076584.

The previous prime is 51123757. The next prime is 51123797. The reversal of 51123791 is 19732115.

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

It is a cyclic number.

It is not a de Polignac number, because 51123791 - 2⁶ = 51123727 is a prime.

It is a super-2 number, since 2×51123791² = 5227284012423362, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51123797) 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, 21941 + ... + 24158.

It is an arithmetic number, because the mean of its divisors is an integer number (12792750).

Almost surely, 2^51123791 is an apocalyptic number.

51123791 is a deficient number, since it is larger than the sum of its proper divisors (47209).

51123791 is a wasteful number, since it uses less digits than its factorization.

51123791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47208.

The product of its digits is 1890, while the sum is 29.

The square root of 51123791 is about 7150.0902791503. The cubic root of 51123791 is about 371.1427803905.

The spelling of 51123791 in words is "fifty-one million, one hundred twenty-three thousand, seven hundred ninety-one".