81574780 has 24 divisors (see below), whose sum is σ = 195779808. Its totient is φ = 27968448.

The previous prime is 81574777. The next prime is 81574781. The reversal of 81574780 is 8747518.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81574781) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 291199 + ... + 291478.

It is an arithmetic number, because the mean of its divisors is an integer number (8157492).

Almost surely, 2^81574780 is an apocalyptic number.

It is an amenable number.

81574780 is an abundant number, since it is smaller than the sum of its proper divisors (114205028).

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

81574780 is a wasteful number, since it uses less digits than its factorization.

81574780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 582693 (or 582691 counting only the distinct ones).

The product of its (nonzero) digits is 62720, while the sum is 40.

The square root of 81574780 is about 9031.8757741678. The cubic root of 81574780 is about 433.6958872440.

The spelling of 81574780 in words is "eighty-one million, five hundred seventy-four thousand, seven hundred eighty".