81489207 has 32 divisors (see below), whose sum is σ = 118632960. Its totient is φ = 49610880.

The previous prime is 81489203. The next prime is 81489227. The reversal of 81489207 is 70298418.

It is not a de Polignac number, because 81489207 - 2² = 81489203 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81489203) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 150357 + ... + 150897.

It is an arithmetic number, because the mean of its divisors is an integer number (3707280).

Almost surely, 2^81489207 is an apocalyptic number.

81489207 is a deficient number, since it is larger than the sum of its proper divisors (37143753).

81489207 is a wasteful number, since it uses less digits than its factorization.

81489207 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 663.

The product of its (nonzero) digits is 32256, while the sum is 39.

The square root of 81489207 is about 9027.1372538585. The cubic root of 81489207 is about 433.5441833189.

The spelling of 81489207 in words is "eighty-one million, four hundred eighty-nine thousand, two hundred seven".