81577405 has 32 divisors (see below), whose sum is σ = 122976000. Its totient is φ = 51621696.

The previous prime is 81577403. The next prime is 81577411. The reversal of 81577405 is 50477518.

It is not a de Polignac number, because 81577405 - 2¹ = 81577403 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81577403) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 20466 + ... + 24124.

It is an arithmetic number, because the mean of its divisors is an integer number (3843000).

Almost surely, 2^81577405 is an apocalyptic number.

It is an amenable number.

81577405 is a deficient number, since it is larger than the sum of its proper divisors (41398595).

81577405 is a wasteful number, since it uses less digits than its factorization.

81577405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3698 (or 3684 counting only the distinct ones).

The product of its (nonzero) digits is 39200, while the sum is 37.

The square root of 81577405 is about 9032.0210916494. The cubic root of 81577405 is about 433.7005391699.

The spelling of 81577405 in words is "eighty-one million, five hundred seventy-seven thousand, four hundred five".