81278751 has 32 divisors (see below), whose sum is σ = 124104960. Its totient is φ = 46987776.

The previous prime is 81278749. The next prime is 81278773. The reversal of 81278751 is 15787218.

It is not a de Polignac number, because 81278751 - 2¹ = 81278749 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81278731) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 34720 + ... + 36986.

It is an arithmetic number, because the mean of its divisors is an integer number (3878280).

Almost surely, 2^81278751 is an apocalyptic number.

81278751 is a deficient number, since it is larger than the sum of its proper divisors (42826209).

81278751 is a wasteful number, since it uses less digits than its factorization.

81278751 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2343.

The product of its digits is 31360, while the sum is 39.

The square root of 81278751 is about 9015.4728661341. The cubic root of 81278751 is about 433.1706343186.

The spelling of 81278751 in words is "eighty-one million, two hundred seventy-eight thousand, seven hundred fifty-one".