81542580 has 48 divisors (see below), whose sum is σ = 260937600. Its totient is φ = 18638208.

The previous prime is 81542507. The next prime is 81542581. The reversal of 81542580 is 8524518.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81542581) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 96655 + ... + 97494.

It is an arithmetic number, because the mean of its divisors is an integer number (5436200).

Almost surely, 2^81542580 is an apocalyptic number.

It is an amenable number.

81542580 is an abundant number, since it is smaller than the sum of its proper divisors (179395020).

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

81542580 is a wasteful number, since it uses less digits than its factorization.

81542580 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 194168 (or 194166 counting only the distinct ones).

The product of its (nonzero) digits is 12800, while the sum is 33.

The square root of 81542580 is about 9030.0930227767. The cubic root of 81542580 is about 433.6388154978.

The spelling of 81542580 in words is "eighty-one million, five hundred forty-two thousand, five hundred eighty".