51040639 has 4 divisors (see below), whose sum is σ = 54966856. Its totient is φ = 47114424.

The previous prime is 51040607. The next prime is 51040727. The reversal of 51040639 is 93604015.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 93604015 = 5 ⋅18720803.

It is a cyclic number.

It is not a de Polignac number, because 51040639 - 2⁵ = 51040607 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 (51044639) 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, 1963089 + ... + 1963114.

It is an arithmetic number, because the mean of its divisors is an integer number (13741714).

Almost surely, 2^51040639 is an apocalyptic number.

51040639 is a deficient number, since it is larger than the sum of its proper divisors (3926217).

51040639 is a wasteful number, since it uses less digits than its factorization.

51040639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3926216.

The product of its (nonzero) digits is 3240, while the sum is 28.

The square root of 51040639 is about 7144.2731610710. The cubic root of 51040639 is about 370.9414520019.

The spelling of 51040639 in words is "fifty-one million, forty thousand, six hundred thirty-nine".