51639823 has 2 divisors, whose sum is σ = 51639824. Its totient is φ = 51639822.

The previous prime is 51639811. The next prime is 51639839. The reversal of 51639823 is 32893615.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51639823 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51639803) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25819911 + 25819912.

It is an arithmetic number, because the mean of its divisors is an integer number (25819912).

Almost surely, 2^51639823 is an apocalyptic number.

51639823 is a deficient number, since it is larger than the sum of its proper divisors (1).

51639823 is an equidigital number, since it uses as much as digits as its factorization.

51639823 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 38880, while the sum is 37.

The square root of 51639823 is about 7186.0853738318. The cubic root of 51639823 is about 372.3873460819.

The spelling of 51639823 in words is "fifty-one million, six hundred thirty-nine thousand, eight hundred twenty-three".