51257861 has 4 divisors (see below), whose sum is σ = 51387372. Its totient is φ = 51128352.

The previous prime is 51257851. The next prime is 51257863. The reversal of 51257861 is 16875215.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 18653761 + 32604100 = 4319^2 + 5710^2 .

It is a cyclic number.

It is not a de Polignac number, because 51257861 - 2⁶ = 51257797 is a prime.

It is a Duffinian number.

It is a plaindrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51257863) 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, 64160 + ... + 64953.

It is an arithmetic number, because the mean of its divisors is an integer number (12846843).

Almost surely, 2^51257861 is an apocalyptic number.

It is an amenable number.

51257861 is a deficient number, since it is larger than the sum of its proper divisors (129511).

51257861 is a wasteful number, since it uses less digits than its factorization.

51257861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 129510.

The product of its digits is 16800, while the sum is 35.

The square root of 51257861 is about 7159.4595466418. The cubic root of 51257861 is about 371.4669326609.

The spelling of 51257861 in words is "fifty-one million, two hundred fifty-seven thousand, eight hundred sixty-one".