51812861 has 4 divisors (see below), whose sum is σ = 52468800. Its totient is φ = 51156924.

The previous prime is 51812843. The next prime is 51812881. The reversal of 51812861 is 16821815.

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 not a de Polignac number, because 51812861 - 2¹⁸ = 51550717 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 (51812801) 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, 327851 + ... + 328008.

It is an arithmetic number, because the mean of its divisors is an integer number (13117200).

Almost surely, 2^51812861 is an apocalyptic number.

It is an amenable number.

51812861 is a deficient number, since it is larger than the sum of its proper divisors (655939).

51812861 is an equidigital number, since it uses as much as digits as its factorization.

51812861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 655938.

The product of its digits is 3840, while the sum is 32.

The square root of 51812861 is about 7198.1151004968. The cubic root of 51812861 is about 372.8028220858.

It can be divided in two parts, 5181 and 2861, that multiplied together give a palindrome (14822841).

The spelling of 51812861 in words is "fifty-one million, eight hundred twelve thousand, eight hundred sixty-one".