81543404 has 6 divisors (see below), whose sum is σ = 142700964. Its totient is φ = 40771700.

The previous prime is 81543401. The next prime is 81543419. The reversal of 81543404 is 40434518.

It is not an unprimeable number, because it can be changed into a prime (81543401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10192922 + ... + 10192929.

It is an arithmetic number, because the mean of its divisors is an integer number (23783494).

Almost surely, 2^81543404 is an apocalyptic number.

It is an amenable number.

81543404 is a deficient number, since it is larger than the sum of its proper divisors (61157560).

81543404 is a wasteful number, since it uses less digits than its factorization.

81543404 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20385855 (or 20385853 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 29.

The square root of 81543404 is about 9030.1386478835. The cubic root of 81543404 is about 433.6402761546.

The spelling of 81543404 in words is "eighty-one million, five hundred forty-three thousand, four hundred four".