81441987 has 16 divisors (see below), whose sum is σ = 118879488. Its totient is φ = 49184480.

The previous prime is 81441977. The next prime is 81442003. The reversal of 81441987 is 78914418.

It is a cyclic number.

It is not a de Polignac number, because 81441987 - 2⁷ = 81441859 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81441937) 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, 5458 + ... + 13880.

It is an arithmetic number, because the mean of its divisors is an integer number (7429968).

Almost surely, 2^81441987 is an apocalyptic number.

81441987 is a deficient number, since it is larger than the sum of its proper divisors (37437501).

81441987 is a wasteful number, since it uses less digits than its factorization.

81441987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8730.

The product of its digits is 64512, while the sum is 42.

The square root of 81441987 is about 9024.5214277545. The cubic root of 81441987 is about 433.4604261663.

It can be divided in two parts, 81441 and 987, that added together give a palindrome (82428).

The spelling of 81441987 in words is "eighty-one million, four hundred forty-one thousand, nine hundred eighty-seven".