81549376 has 14 divisors (see below), whose sum is σ = 161824670. Its totient is φ = 40774656.

The previous prime is 81549373. The next prime is 81549379. The reversal of 81549376 is 67394518.

It is an interprime number because it is at equal distance from previous prime (81549373) and next prime (81549379).

It can be written as a sum of positive squares in only one way, i.e., 77862976 + 3686400 = 8824^2 + 1920^2 .

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 as a sum of consecutive naturals, namely, 637041 + ... + 637168.

It is an arithmetic number, because the mean of its divisors is an integer number (11558905).

Almost surely, 2^81549376 is an apocalyptic number.

It is an amenable number.

81549376 is a deficient number, since it is larger than the sum of its proper divisors (80275294).

81549376 is a wasteful number, since it uses less digits than its factorization.

81549376 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1274221 (or 1274211 counting only the distinct ones).

The product of its digits is 181440, while the sum is 43.

The square root of 81549376 is about 9030.4693122783. The cubic root of 81549376 is about 433.6508620773.

The spelling of 81549376 in words is "eighty-one million, five hundred forty-nine thousand, three hundred seventy-six".