51779991 has 4 divisors (see below), whose sum is σ = 69039992. Its totient is φ = 34519992.

The previous prime is 51779989. The next prime is 51780017. The reversal of 51779991 is 19997715.

It is a happy number.

51779991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 51779991 - 2¹ = 51779989 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 51779991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51779941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8629996 + ... + 8630001.

It is an arithmetic number, because the mean of its divisors is an integer number (17259998).

Almost surely, 2^51779991 is an apocalyptic number.

51779991 is a deficient number, since it is larger than the sum of its proper divisors (17260001).

51779991 is a wasteful number, since it uses less digits than its factorization.

51779991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17260000.

The product of its digits is 178605, while the sum is 48.

The square root of 51779991 is about 7195.8315016404. The cubic root of 51779991 is about 372.7239702283.

It can be divided in two parts, 517 and 79991, that added together give a palindrome (80508).

The spelling of 51779991 in words is "fifty-one million, seven hundred seventy-nine thousand, nine hundred ninety-one".