51421693 has 4 divisors (see below), whose sum is σ = 51485148. Its totient is φ = 51358240.

The previous prime is 51421687. The next prime is 51421703. The reversal of 51421693 is 39612415.

51421693 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, and also an emirpimes, since its reverse is a distinct semiprime: 39612415 = 5 ⋅7922483.

It can be written as a sum of positive squares in 2 ways, for example, as 11819844 + 39601849 = 3438^2 + 6293^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51421693 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51421603) 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, 30496 + ... + 32137.

It is an arithmetic number, because the mean of its divisors is an integer number (12871287).

Almost surely, 2^51421693 is an apocalyptic number.

It is an amenable number.

51421693 is a deficient number, since it is larger than the sum of its proper divisors (63455).

51421693 is an equidigital number, since it uses as much as digits as its factorization.

51421693 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63454.

The product of its digits is 6480, while the sum is 31.

The square root of 51421693 is about 7170.8920644506. The cubic root of 51421693 is about 371.8622765508.

The spelling of 51421693 in words is "fifty-one million, four hundred twenty-one thousand, six hundred ninety-three".