51139639 has 8 divisors (see below), whose sum is σ = 52323920. Its totient is φ = 49968576.

The previous prime is 51139637. The next prime is 51139643. The reversal of 51139639 is 93693115.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 51139639 - 2¹ = 51139637 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 51139598 and 51139607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51139637) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4744 + ... + 11170.

It is an arithmetic number, because the mean of its divisors is an integer number (6540490).

Almost surely, 2^51139639 is an apocalyptic number.

51139639 is a deficient number, since it is larger than the sum of its proper divisors (1184281).

51139639 is a wasteful number, since it uses less digits than its factorization.

51139639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6609.

The product of its digits is 21870, while the sum is 37.

The square root of 51139639 is about 7151.1984310324. The cubic root of 51139639 is about 371.1811269411.

The spelling of 51139639 in words is "fifty-one million, one hundred thirty-nine thousand, six hundred thirty-nine".