51689321 has 2 divisors, whose sum is σ = 51689322. Its totient is φ = 51689320.

The previous prime is 51689317. The next prime is 51689327. The reversal of 51689321 is 12398615.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 42719296 + 8970025 = 6536^2 + 2995^2 .

It is a cyclic number.

It is not a de Polignac number, because 51689321 - 2² = 51689317 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (51689327) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25844660 + 25844661.

It is an arithmetic number, because the mean of its divisors is an integer number (25844661).

Almost surely, 2^51689321 is an apocalyptic number.

It is an amenable number.

51689321 is a deficient number, since it is larger than the sum of its proper divisors (1).

51689321 is an equidigital number, since it uses as much as digits as its factorization.

51689321 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12960, while the sum is 35.

The square root of 51689321 is about 7189.5285659075. The cubic root of 51689321 is about 372.5062887997.

The spelling of 51689321 in words is "fifty-one million, six hundred eighty-nine thousand, three hundred twenty-one".