51138257 has 4 divisors (see below), whose sum is σ = 51179520. Its totient is φ = 51096996.

The previous prime is 51138229. The next prime is 51138271. The reversal of 51138257 is 75283115.

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.

It is a cyclic number.

It is not a de Polignac number, because 51138257 - 2⁸ = 51138001 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51138277) 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, 18713 + ... + 21270.

It is an arithmetic number, because the mean of its divisors is an integer number (12794880).

Almost surely, 2^51138257 is an apocalyptic number.

It is an amenable number.

51138257 is a deficient number, since it is larger than the sum of its proper divisors (41263).

51138257 is a wasteful number, since it uses less digits than its factorization.

51138257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41262.

The product of its digits is 8400, while the sum is 32.

The square root of 51138257 is about 7151.1018032189. The cubic root of 51138257 is about 371.1777833056.

The spelling of 51138257 in words is "fifty-one million, one hundred thirty-eight thousand, two hundred fifty-seven".