255321821 has 2 divisors, whose sum is σ = 255321822. Its totient is φ = 255321820.

The previous prime is 255321817. The next prime is 255321863. The reversal of 255321821 is 128123552.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 152522500 + 102799321 = 12350^2 + 10139^2 .

It is a cyclic number.

It is not a de Polignac number, because 255321821 - 2² = 255321817 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (255321881) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 127660910 + 127660911.

It is an arithmetic number, because the mean of its divisors is an integer number (127660911).

Almost surely, 2^255321821 is an apocalyptic number.

It is an amenable number.

255321821 is a deficient number, since it is larger than the sum of its proper divisors (1).

255321821 is an equidigital number, since it uses as much as digits as its factorization.

255321821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4800, while the sum is 29.

The square root of 255321821 is about 15978.7928517770. The cubic root of 255321821 is about 634.3992259460.

The spelling of 255321821 in words is "two hundred fifty-five million, three hundred twenty-one thousand, eight hundred twenty-one".