51319821 has 32 divisors (see below), whose sum is σ = 85674240. Its totient is φ = 26643456.

The previous prime is 51319819. The next prime is 51319841. The reversal of 51319821 is 12891315.

It is not a de Polignac number, because 51319821 - 2¹ = 51319819 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51319841) 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 31 ways as a sum of consecutive naturals, for example, 7875 + ... + 12831.

It is an arithmetic number, because the mean of its divisors is an integer number (2677320).

Almost surely, 2^51319821 is an apocalyptic number.

51319821 is a gapful number since it is divisible by the number (51) formed by its first and last digit.

It is an amenable number.

51319821 is a deficient number, since it is larger than the sum of its proper divisors (34354419).

51319821 is a wasteful number, since it uses less digits than its factorization.

51319821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5013.

The product of its digits is 2160, while the sum is 30.

The square root of 51319821 is about 7163.7853820449. The cubic root of 51319821 is about 371.6165475886.

The spelling of 51319821 in words is "fifty-one million, three hundred nineteen thousand, eight hundred twenty-one".