81267751 has 4 divisors (see below), whose sum is σ = 81567904. Its totient is φ = 80967600.

The previous prime is 81267713. The next prime is 81267787. The reversal of 81267751 is 15776218.

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

It is a cyclic number.

It is not a de Polignac number, because 81267751 - 2⁷ = 81267623 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81267751.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81267551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 149670 + ... + 150211.

It is an arithmetic number, because the mean of its divisors is an integer number (20391976).

Almost surely, 2^81267751 is an apocalyptic number.

81267751 is a deficient number, since it is larger than the sum of its proper divisors (300153).

81267751 is a wasteful number, since it uses less digits than its factorization.

81267751 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 300152.

The product of its digits is 23520, while the sum is 37.

The square root of 81267751 is about 9014.8627832042. The cubic root of 81267751 is about 433.1510921386.

The spelling of 81267751 in words is "eighty-one million, two hundred sixty-seven thousand, seven hundred fifty-one".