181990465 has 8 divisors (see below), whose sum is σ = 218464488. Its totient is φ = 145541760.

The previous prime is 181990411. The next prime is 181990469. The reversal of 181990465 is 564099181.

It can be written as a sum of positive squares in 4 ways, for example, as 19963024 + 162027441 = 4468^2 + 12729^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 181990465 - 2²¹ = 179893313 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (181990469) 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 in 7 ways as a sum of consecutive naturals, for example, 17989 + ... + 26221.

It is an arithmetic number, because the mean of its divisors is an integer number (27308061).

Almost surely, 2^181990465 is an apocalyptic number.

It is an amenable number.

181990465 is a deficient number, since it is larger than the sum of its proper divisors (36474023).

181990465 is an equidigital number, since it uses as much as digits as its factorization.

181990465 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12659.

The product of its (nonzero) digits is 77760, while the sum is 43.

The square root of 181990465 is about 13490.3841679917. The cubic root of 181990465 is about 566.6952140559.

The spelling of 181990465 in words is "one hundred eighty-one million, nine hundred ninety thousand, four hundred sixty-five".