81641146 has 4 divisors (see below), whose sum is σ = 122461722. Its totient is φ = 40820572.

The previous prime is 81641141. The next prime is 81641171. The reversal of 81641146 is 64114618.

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., 64625521 + 17015625 = 8039^2 + 4125^2 .

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (81641141) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20410285 + ... + 20410288.

Almost surely, 2^81641146 is an apocalyptic number.

81641146 is a deficient number, since it is larger than the sum of its proper divisors (40820576).

81641146 is a wasteful number, since it uses less digits than its factorization.

81641146 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40820575.

The product of its digits is 4608, while the sum is 31.

The square root of 81641146 is about 9035.5490148635. The cubic root of 81641146 is about 433.8134679444.

The spelling of 81641146 in words is "eighty-one million, six hundred forty-one thousand, one hundred forty-six".