81287461 has 8 divisors (see below), whose sum is σ = 84276864. Its totient is φ = 78346080.

The previous prime is 81287447. The next prime is 81287467. The reversal of 81287461 is 16478218.

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

It is not a de Polignac number, because 81287461 - 2⁵ = 81287429 is a prime.

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 81287461.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81287467) 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, 8541 + ... + 15346.

It is an arithmetic number, because the mean of its divisors is an integer number (10534608).

Almost surely, 2^81287461 is an apocalyptic number.

It is an amenable number.

81287461 is a deficient number, since it is larger than the sum of its proper divisors (2989403).

81287461 is a wasteful number, since it uses less digits than its factorization.

81287461 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24011.

The product of its digits is 21504, while the sum is 37.

The square root of 81287461 is about 9015.9559116047. The cubic root of 81287461 is about 433.1861069212.

The spelling of 81287461 in words is "eighty-one million, two hundred eighty-seven thousand, four hundred sixty-one".