81545089 has 4 divisors (see below), whose sum is σ = 81563860. Its totient is φ = 81526320.

The previous prime is 81545053. The next prime is 81545099. The reversal of 81545089 is 98054518.

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

It can be written as a sum of positive squares in 2 ways, for example, as 32433025 + 49112064 = 5695^2 + 7008^2 .

It is a cyclic number.

It is not a de Polignac number, because 81545089 - 2⁷ = 81544961 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81545029) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 859 + ... + 12799.

It is an arithmetic number, because the mean of its divisors is an integer number (20390965).

Almost surely, 2^81545089 is an apocalyptic number.

It is an amenable number.

81545089 is a deficient number, since it is larger than the sum of its proper divisors (18771).

81545089 is a wasteful number, since it uses less digits than its factorization.

81545089 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18770.

The product of its (nonzero) digits is 57600, while the sum is 40.

The square root of 81545089 is about 9030.2319460798. The cubic root of 81545089 is about 433.6432630254.

The spelling of 81545089 in words is "eighty-one million, five hundred forty-five thousand, eighty-nine".