81361151 has 4 divisors (see below), whose sum is σ = 81397704. Its totient is φ = 81324600.

The previous prime is 81361141. The next prime is 81361157. The reversal of 81361151 is 15116318.

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 81361151 - 2¹⁰ = 81360127 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81361151.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81361157) 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, 14705 + ... + 19466.

It is an arithmetic number, because the mean of its divisors is an integer number (20349426).

Almost surely, 2^81361151 is an apocalyptic number.

81361151 is a deficient number, since it is larger than the sum of its proper divisors (36553).

81361151 is a wasteful number, since it uses less digits than its factorization.

81361151 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36552.

The product of its digits is 720, while the sum is 26.

The square root of 81361151 is about 9020.0416296157. The cubic root of 81361151 is about 433.3169669690.

Adding to 81361151 its reverse (15116318), we get a palindrome (96477469).

The spelling of 81361151 in words is "eighty-one million, three hundred sixty-one thousand, one hundred fifty-one".