181261636 has 6 divisors (see below), whose sum is σ = 317207870. Its totient is φ = 90630816.

The previous prime is 181261627. The next prime is 181261637. The reversal of 181261636 is 636162181.

It is a happy number.

181261636 is digitally balanced in base 2 and base 3, because in such bases it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 148840000 + 32421636 = 12200^2 + 5694^2 .

It is not an unprimeable number, because it can be changed into a prime (181261637) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 22657701 + ... + 22657708.

Almost surely, 2^181261636 is an apocalyptic number.

It is an amenable number.

181261636 is a deficient number, since it is larger than the sum of its proper divisors (135946234).

181261636 is a wasteful number, since it uses less digits than its factorization.

181261636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45315413 (or 45315411 counting only the distinct ones).

The product of its digits is 10368, while the sum is 34.

The square root of 181261636 is about 13463.3441610916. The cubic root of 181261636 is about 565.9377082699.

The spelling of 181261636 in words is "one hundred eighty-one million, two hundred sixty-one thousand, six hundred thirty-six".