81279375 has 40 divisors (see below), whose sum is σ = 137655936. Its totient is φ = 42636000.

The previous prime is 81279353. The next prime is 81279377. The reversal of 81279375 is 57397218.

It is not a de Polignac number, because 81279375 - 2⁸ = 81279119 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81279377) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 125302 + ... + 125948.

Almost surely, 2^81279375 is an apocalyptic number.

81279375 is a deficient number, since it is larger than the sum of its proper divisors (56376561).

81279375 is an equidigital number, since it uses as much as digits as its factorization.

81279375 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 737 (or 722 counting only the distinct ones).

The product of its digits is 105840, while the sum is 42.

The square root of 81279375 is about 9015.5074732374. The cubic root of 81279375 is about 433.1717428403.

The spelling of 81279375 in words is "eighty-one million, two hundred seventy-nine thousand, three hundred seventy-five".