51345123421 has 4 divisors (see below), whose sum is σ = 51424976512. Its totient is φ = 51265270332.

The previous prime is 51345123407. The next prime is 51345123449. The reversal of 51345123421 is 12432154315.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 51345123421 - 2⁹ = 51345122909 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 (51345123491) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 39925581 + ... + 39926866.

It is an arithmetic number, because the mean of its divisors is an integer number (12856244128).

Almost surely, 2^51345123421 is an apocalyptic number.

It is an amenable number.

51345123421 is a deficient number, since it is larger than the sum of its proper divisors (79853091).

51345123421 is an equidigital number, since it uses as much as digits as its factorization.

51345123421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79853090.

The product of its digits is 14400, while the sum is 31.

Adding to 51345123421 its reverse (12432154315), we get a palindrome (63777277736).

The spelling of 51345123421 in words is "fifty-one billion, three hundred forty-five million, one hundred twenty-three thousand, four hundred twenty-one".