81149751 has 12 divisors (see below), whose sum is σ = 117306280. Its totient is φ = 54058320.

The previous prime is 81149749. The next prime is 81149759. The reversal of 81149751 is 15794118.

It is not a de Polignac number, because 81149751 - 2¹ = 81149749 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81149759) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 13080 + ... + 18258.

Almost surely, 2^81149751 is an apocalyptic number.

81149751 is a deficient number, since it is larger than the sum of its proper divisors (36156529).

81149751 is a wasteful number, since it uses less digits than its factorization.

81149751 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6926 (or 6923 counting only the distinct ones).

The product of its digits is 10080, while the sum is 36.

The square root of 81149751 is about 9008.3156583237. The cubic root of 81149751 is about 432.9413468370.

The spelling of 81149751 in words is "eighty-one million, one hundred forty-nine thousand, seven hundred fifty-one".