51506642501 has 4 divisors (see below), whose sum is σ = 51626147904. Its totient is φ = 51387137100.

The previous prime is 51506642489. The next prime is 51506642521. The reversal of 51506642501 is 10524660515.

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, and also an emirpimes, since its reverse is a distinct semiprime: 10524660515 = 5 ⋅2104932103.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51506642501 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51506642521) 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, 59752055 + ... + 59752916.

It is an arithmetic number, because the mean of its divisors is an integer number (12906536976).

Almost surely, 2^51506642501 is an apocalyptic number.

It is an amenable number.

51506642501 is a deficient number, since it is larger than the sum of its proper divisors (119505403).

51506642501 is a wasteful number, since it uses less digits than its factorization.

51506642501 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 119505402.

The product of its (nonzero) digits is 36000, while the sum is 35.

The spelling of 51506642501 in words is "fifty-one billion, five hundred six million, six hundred forty-two thousand, five hundred one".