81287057 has 4 divisors (see below), whose sum is σ = 81310320. Its totient is φ = 81263796.

The previous prime is 81287027. The next prime is 81287069. The reversal of 81287057 is 75078218.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81287057 - 2¹⁰ = 81286033 is a prime.

It is a super-3 number, since 3×81287057³ (a number of 25 digits) contains 333 as substring.

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 81287057.

It is not an unprimeable number, because it can be changed into a prime (81287027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5207 + ... + 13772.

It is an arithmetic number, because the mean of its divisors is an integer number (20327580).

Almost surely, 2^81287057 is an apocalyptic number.

It is an amenable number.

81287057 is a deficient number, since it is larger than the sum of its proper divisors (23263).

81287057 is a wasteful number, since it uses less digits than its factorization.

81287057 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23262.

The product of its (nonzero) digits is 31360, while the sum is 38.

The square root of 81287057 is about 9015.9335068533. The cubic root of 81287057 is about 433.1853892727.

The spelling of 81287057 in words is "eighty-one million, two hundred eighty-seven thousand, fifty-seven".