81207549 has 16 divisors (see below), whose sum is σ = 125539200. Its totient is φ = 51784128.

The previous prime is 81207517. The next prime is 81207559. The reversal of 81207549 is 94570218.

It is not a de Polignac number, because 81207549 - 2⁵ = 81207517 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81207559) 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, 64764 + ... + 66005.

It is an arithmetic number, because the mean of its divisors is an integer number (7846200).

Almost surely, 2^81207549 is an apocalyptic number.

It is an amenable number.

81207549 is a deficient number, since it is larger than the sum of its proper divisors (44331651).

81207549 is a wasteful number, since it uses less digits than its factorization.

81207549 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 130801 (or 130795 counting only the distinct ones).

The product of its (nonzero) digits is 20160, while the sum is 36.

The square root of 81207549 is about 9011.5231232018. The cubic root of 81207549 is about 433.0441083168.

The spelling of 81207549 in words is "eighty-one million, two hundred seven thousand, five hundred forty-nine".