51691449139 has 24 divisors (see below), whose sum is σ = 58326054080. Its totient is φ = 45761189760.

The previous prime is 51691449071. The next prime is 51691449151. The reversal of 51691449139 is 93194419615.

It is not a de Polignac number, because 51691449139 - 2³¹ = 49543965491 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51691449179) 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, 660769 + ... + 734845.

Almost surely, 2^51691449139 is an apocalyptic number.

51691449139 is a deficient number, since it is larger than the sum of its proper divisors (6634604941).

51691449139 is a wasteful number, since it uses less digits than its factorization.

51691449139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74251 (or 74240 counting only the distinct ones).

The product of its digits is 1049760, while the sum is 52.

The spelling of 51691449139 in words is "fifty-one billion, six hundred ninety-one million, four hundred forty-nine thousand, one hundred thirty-nine".