51646399 has 4 divisors (see below), whose sum is σ = 59024464. Its totient is φ = 44268336.

The previous prime is 51646393. The next prime is 51646409. The reversal of 51646399 is 99364615.

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

It is not a de Polignac number, because 51646399 - 2⁹ = 51645887 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 (51646393) 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, 3689022 + ... + 3689035.

It is an arithmetic number, because the mean of its divisors is an integer number (14756116).

Almost surely, 2^51646399 is an apocalyptic number.

51646399 is a deficient number, since it is larger than the sum of its proper divisors (7378065).

51646399 is an equidigital number, since it uses as much as digits as its factorization.

51646399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7378064.

The product of its digits is 174960, while the sum is 43.

The square root of 51646399 is about 7186.5429101899. The cubic root of 51646399 is about 372.4031524571.

The spelling of 51646399 in words is "fifty-one million, six hundred forty-six thousand, three hundred ninety-nine".