81731552 has 24 divisors (see below), whose sum is σ = 183896496. Its totient is φ = 35027712.

The previous prime is 81731549. The next prime is 81731561. The reversal of 81731552 is 25513718.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 182213 + ... + 182660.

It is an arithmetic number, because the mean of its divisors is an integer number (7662354).

Almost surely, 2^81731552 is an apocalyptic number.

It is an amenable number.

81731552 is an abundant number, since it is smaller than the sum of its proper divisors (102164944).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81731552 is a wasteful number, since it uses less digits than its factorization.

81731552 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 364890 (or 364882 counting only the distinct ones).

The product of its digits is 8400, while the sum is 32.

The square root of 81731552 is about 9040.5504257208. The cubic root of 81731552 is about 433.9735378544.

The spelling of 81731552 in words is "eighty-one million, seven hundred thirty-one thousand, five hundred fifty-two".