73581821 has 2 divisors, whose sum is σ = 73581822. Its totient is φ = 73581820.

The previous prime is 73581811. The next prime is 73581869. The reversal of 73581821 is 12818537.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 70644025 + 2937796 = 8405^2 + 1714^2 .

It is a cyclic number.

It is not a de Polignac number, because 73581821 - 2¹⁸ = 73319677 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (73581811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36790910 + 36790911.

It is an arithmetic number, because the mean of its divisors is an integer number (36790911).

Almost surely, 2^73581821 is an apocalyptic number.

It is an amenable number.

73581821 is a deficient number, since it is larger than the sum of its proper divisors (1).

73581821 is an equidigital number, since it uses as much as digits as its factorization.

73581821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13440, while the sum is 35.

The square root of 73581821 is about 8577.9846700726. The cubic root of 73581821 is about 419.0413148978.

The spelling of 73581821 in words is "seventy-three million, five hundred eighty-one thousand, eight hundred twenty-one".