81275381 has 16 divisors (see below), whose sum is σ = 90201600. Its totient is φ = 72618480.

The previous prime is 81275377. The next prime is 81275431. The reversal of 81275381 is 18357218.

It is not a de Polignac number, because 81275381 - 2² = 81275377 is a prime.

It is a super-3 number, since 3×81275381³ (a number of 25 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81275321) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 234050 + ... + 234396.

It is an arithmetic number, because the mean of its divisors is an integer number (5637600).

Almost surely, 2^81275381 is an apocalyptic number.

It is an amenable number.

81275381 is a deficient number, since it is larger than the sum of its proper divisors (8926219).

81275381 is a wasteful number, since it uses less digits than its factorization.

81275381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 664.

The product of its digits is 13440, while the sum is 35.

The square root of 81275381 is about 9015.2859632959. The cubic root of 81275381 is about 433.1646474926.

The spelling of 81275381 in words is "eighty-one million, two hundred seventy-five thousand, three hundred eighty-one".