81481387 has 16 divisors (see below), whose sum is σ = 94731840. Its totient is φ = 69455232.

The previous prime is 81481381. The next prime is 81481397. The reversal of 81481387 is 78318418.

It is not a de Polignac number, because 81481387 - 2¹⁹ = 80957099 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81481381) 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, 3973 + ... + 13369.

It is an arithmetic number, because the mean of its divisors is an integer number (5920740).

Almost surely, 2^81481387 is an apocalyptic number.

81481387 is a deficient number, since it is larger than the sum of its proper divisors (13250453).

81481387 is a wasteful number, since it uses less digits than its factorization.

81481387 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9462.

The product of its digits is 43008, while the sum is 40.

The square root of 81481387 is about 9026.7041050430. The cubic root of 81481387 is about 433.5303147176.

The spelling of 81481387 in words is "eighty-one million, four hundred eighty-one thousand, three hundred eighty-seven".