81449477 has 4 divisors (see below), whose sum is σ = 82430880. Its totient is φ = 80468076.

The previous prime is 81449437. The next prime is 81449479. The reversal of 81449477 is 77494418.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81449477 - 2¹⁰ = 81448453 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81449479) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 490577 + ... + 490742.

It is an arithmetic number, because the mean of its divisors is an integer number (20607720).

Almost surely, 2^81449477 is an apocalyptic number.

It is an amenable number.

81449477 is a deficient number, since it is larger than the sum of its proper divisors (981403).

81449477 is an equidigital number, since it uses as much as digits as its factorization.

81449477 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 981402.

The product of its digits is 225792, while the sum is 44.

The square root of 81449477 is about 9024.9363986679. The cubic root of 81449477 is about 433.4737138212.

The spelling of 81449477 in words is "eighty-one million, four hundred forty-nine thousand, four hundred seventy-seven".