81551303 has 4 divisors (see below), whose sum is σ = 81861648. Its totient is φ = 81240960.

The previous prime is 81551291. The next prime is 81551311. The reversal of 81551303 is 30315518.

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

It is a cyclic number.

It is not a de Polignac number, because 81551303 - 2¹⁴ = 81534919 is a prime.

It is a cake number, because a cake can be divided into 81551303 parts by 788 planar cuts.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81551333) 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 3 ways as a sum of consecutive naturals, for example, 154778 + ... + 155303.

It is an arithmetic number, because the mean of its divisors is an integer number (20465412).

Almost surely, 2^81551303 is an apocalyptic number.

81551303 is a deficient number, since it is larger than the sum of its proper divisors (310345).

81551303 is a wasteful number, since it uses less digits than its factorization.

81551303 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 310344.

The product of its (nonzero) digits is 1800, while the sum is 26.

The square root of 81551303 is about 9030.5760059921. The cubic root of 81551303 is about 433.6542777528.

The spelling of 81551303 in words is "eighty-one million, five hundred fifty-one thousand, three hundred three".