51164021 has 4 divisors (see below), whose sum is σ = 51864972. Its totient is φ = 50463072.

The previous prime is 51164011. The next prime is 51164039. The reversal of 51164021 is 12046115.

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 23716900 + 27447121 = 4870^2 + 5239^2 .

It is a cyclic number.

It is not a de Polignac number, because 51164021 - 2¹⁰ = 51162997 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 51163984 and 51164002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51164011) 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, 350366 + ... + 350511.

It is an arithmetic number, because the mean of its divisors is an integer number (12966243).

Almost surely, 2^51164021 is an apocalyptic number.

It is an amenable number.

51164021 is a deficient number, since it is larger than the sum of its proper divisors (700951).

51164021 is an equidigital number, since it uses as much as digits as its factorization.

51164021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 700950.

The product of its (nonzero) digits is 240, while the sum is 20.

The square root of 51164021 is about 7152.9029771136. The cubic root of 51164021 is about 371.2401072840.

The spelling of 51164021 in words is "fifty-one million, one hundred sixty-four thousand, twenty-one".