81549371 has 8 divisors (see below), whose sum is σ = 85223424. Its totient is φ = 77956200.

The previous prime is 81549361. The next prime is 81549373. The reversal of 81549371 is 17394518.

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

It is a cyclic number.

It is not a de Polignac number, because 81549371 - 2¹⁴ = 81532987 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81549373) 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, 18155 + ... + 22196.

It is an arithmetic number, because the mean of its divisors is an integer number (10652928).

Almost surely, 2^81549371 is an apocalyptic number.

81549371 is a deficient number, since it is larger than the sum of its proper divisors (3674053).

81549371 is a wasteful number, since it uses less digits than its factorization.

81549371 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40441.

The product of its digits is 30240, while the sum is 38.

The square root of 81549371 is about 9030.4690354377. The cubic root of 81549371 is about 433.6508532145.

The spelling of 81549371 in words is "eighty-one million, five hundred forty-nine thousand, three hundred seventy-one".