81275919 has 8 divisors (see below), whose sum is σ = 108994992. Its totient is φ = 53870400.

The previous prime is 81275879. The next prime is 81275921. The reversal of 81275919 is 91957218.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 81275919 - 2¹² = 81271823 is a prime.

It is a super-2 number, since 2×81275919² = 13211550018589122, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81275219) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 77782 + ... + 78819.

It is an arithmetic number, because the mean of its divisors is an integer number (13624374).

Almost surely, 2^81275919 is an apocalyptic number.

81275919 is a deficient number, since it is larger than the sum of its proper divisors (27719073).

81275919 is a wasteful number, since it uses less digits than its factorization.

81275919 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 156777.

The product of its digits is 45360, while the sum is 42.

The square root of 81275919 is about 9015.3158014570. The cubic root of 81275919 is about 433.1656032640.

The spelling of 81275919 in words is "eighty-one million, two hundred seventy-five thousand, nine hundred nineteen".