181681634 has 4 divisors (see below), whose sum is σ = 272522454. Its totient is φ = 90840816.

The previous prime is 181681603. The next prime is 181681637. The reversal of 181681634 is 436186181.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 120012025 + 61669609 = 10955^2 + 7853^2 .

It is a super-2 number, since 2×181681634² = 66016432265819912, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (181681637) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45420407 + ... + 45420410.

Almost surely, 2^181681634 is an apocalyptic number.

181681634 is a deficient number, since it is larger than the sum of its proper divisors (90840820).

181681634 is an equidigital number, since it uses as much as digits as its factorization.

181681634 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90840819.

The product of its digits is 27648, while the sum is 38.

The square root of 181681634 is about 13478.9329696382. The cubic root of 181681634 is about 566.3744790475.

The spelling of 181681634 in words is "one hundred eighty-one million, six hundred eighty-one thousand, six hundred thirty-four".