81550453 has 4 divisors (see below), whose sum is σ = 81711180. Its totient is φ = 81389728.

The previous prime is 81550409. The next prime is 81550459. The reversal of 81550453 is 35405518.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 35405518 = 2 ⋅17702759.

It can be written as a sum of positive squares in 2 ways, for example, as 44863204 + 36687249 = 6698^2 + 6057^2 .

It is a cyclic number.

It is not a de Polignac number, because 81550453 - 2¹³ = 81542261 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81550459) 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, 79600 + ... + 80617.

It is an arithmetic number, because the mean of its divisors is an integer number (20427795).

Almost surely, 2^81550453 is an apocalyptic number.

It is an amenable number.

81550453 is a deficient number, since it is larger than the sum of its proper divisors (160727).

81550453 is a wasteful number, since it uses less digits than its factorization.

81550453 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 160726.

The product of its (nonzero) digits is 12000, while the sum is 31.

The square root of 81550453 is about 9030.5289435337. The cubic root of 81550453 is about 433.6527711045.

The spelling of 81550453 in words is "eighty-one million, five hundred fifty thousand, four hundred fifty-three".