73181921 has 2 divisors, whose sum is σ = 73181922. Its totient is φ = 73181920.

The previous prime is 73181897. The next prime is 73181951. The reversal of 73181921 is 12918137.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 47059600 + 26122321 = 6860^2 + 5111^2 .

It is a cyclic number.

It is not a de Polignac number, because 73181921 - 2¹⁴ = 73165537 is a prime.

It is a super-2 number, since 2×73181921² = 10711187122500482, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (73181951) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36590960 + 36590961.

It is an arithmetic number, because the mean of its divisors is an integer number (36590961).

Almost surely, 2^73181921 is an apocalyptic number.

It is an amenable number.

73181921 is a deficient number, since it is larger than the sum of its proper divisors (1).

73181921 is an equidigital number, since it uses as much as digits as its factorization.

73181921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3024, while the sum is 32.

The square root of 73181921 is about 8554.6432421230. The cubic root of 73181921 is about 418.2808049613.

The spelling of 73181921 in words is "seventy-three million, one hundred eighty-one thousand, nine hundred twenty-one".