51138615 has 16 divisors (see below), whose sum is σ = 89260416. Its totient is φ = 24794400.

The previous prime is 51138613. The next prime is 51138641. The reversal of 51138615 is 51683115.

It is not a de Polignac number, because 51138615 - 2¹ = 51138613 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51138611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 154801 + ... + 155130.

It is an arithmetic number, because the mean of its divisors is an integer number (5578776).

Almost surely, 2^51138615 is an apocalyptic number.

51138615 is a gapful number since it is divisible by the number (55) formed by its first and last digit.

51138615 is a deficient number, since it is larger than the sum of its proper divisors (38121801).

51138615 is a wasteful number, since it uses less digits than its factorization.

51138615 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 309950.

The product of its digits is 3600, while the sum is 30.

The square root of 51138615 is about 7151.1268342828. The cubic root of 51138615 is about 371.1786494630.

The spelling of 51138615 in words is "fifty-one million, one hundred thirty-eight thousand, six hundred fifteen".