80451821 has 2 divisors, whose sum is σ = 80451822. Its totient is φ = 80451820.

The previous prime is 80451809. The next prime is 80451841. The reversal of 80451821 is 12815408.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 77193796 + 3258025 = 8786^2 + 1805^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-80451821 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (80451841) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40225910 + 40225911.

It is an arithmetic number, because the mean of its divisors is an integer number (40225911).

Almost surely, 2^80451821 is an apocalyptic number.

It is an amenable number.

80451821 is a deficient number, since it is larger than the sum of its proper divisors (1).

80451821 is an equidigital number, since it uses as much as digits as its factorization.

80451821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2560, while the sum is 29.

The square root of 80451821 is about 8969.4939099149. The cubic root of 80451821 is about 431.6965980216.

It can be divided in two parts, 80451 and 821, that multiplied together give a triangular number (66050271 = T₁₁₄₉₃).

The spelling of 80451821 in words is "eighty million, four hundred fifty-one thousand, eight hundred twenty-one".