81528386 has 4 divisors (see below), whose sum is σ = 122292582. Its totient is φ = 40764192.

The previous prime is 81528341. The next prime is 81528389. The reversal of 81528386 is 68382518.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 80013025 + 1515361 = 8945^2 + 1231^2 .

It is not an unprimeable number, because it can be changed into a prime (81528389) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20382095 + ... + 20382098.

Almost surely, 2^81528386 is an apocalyptic number.

81528386 is a deficient number, since it is larger than the sum of its proper divisors (40764196).

81528386 is a wasteful number, since it uses less digits than its factorization.

81528386 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40764195.

The product of its digits is 92160, while the sum is 41.

The square root of 81528386 is about 9029.3070608990. The cubic root of 81528386 is about 433.6136530754.

The spelling of 81528386 in words is "eighty-one million, five hundred twenty-eight thousand, three hundred eighty-six".