51209803939 has 24 divisors (see below), whose sum is σ = 60113884160. Its totient is φ = 42711172560.

The previous prime is 51209803937. The next prime is 51209803949. The reversal of 51209803939 is 93930890215.

It is not a de Polignac number, because 51209803939 - 2¹ = 51209803937 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 51209803892 and 51209803901.

It is not an unprimeable number, because it can be changed into a prime (51209803937) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 29112142 + ... + 29113900.

Almost surely, 2^51209803939 is an apocalyptic number.

51209803939 is a deficient number, since it is larger than the sum of its proper divisors (8904080221).

51209803939 is an equidigital number, since it uses as much as digits as its factorization.

51209803939 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2431 (or 2120 counting only the distinct ones).

The product of its (nonzero) digits is 524880, while the sum is 49.

The spelling of 51209803939 in words is "fifty-one billion, two hundred nine million, eight hundred three thousand, nine hundred thirty-nine".