81131146 has 4 divisors (see below), whose sum is σ = 121696722. Its totient is φ = 40565572.

The previous prime is 81131137. The next prime is 81131147. The reversal of 81131146 is 64113118.

It is a happy number.

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., 61230625 + 19900521 = 7825^2 + 4461^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 81131146.

It is not an unprimeable number, because it can be changed into a prime (81131147) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20282785 + ... + 20282788.

Almost surely, 2^81131146 is an apocalyptic number.

81131146 is a deficient number, since it is larger than the sum of its proper divisors (40565576).

81131146 is a wasteful number, since it uses less digits than its factorization.

81131146 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40565575.

The product of its digits is 576, while the sum is 25.

The square root of 81131146 is about 9007.2829421530. The cubic root of 81131146 is about 432.9082578490.

The spelling of 81131146 in words is "eighty-one million, one hundred thirty-one thousand, one hundred forty-six".