81813051 has 8 divisors (see below), whose sum is σ = 121204560. Its totient is φ = 54542016.

The previous prime is 81813049. The next prime is 81813077. The reversal of 81813051 is 15031818.

It is not a de Polignac number, because 81813051 - 2¹ = 81813049 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 3030113 = 81813051 / (8 + 1 + 8 + 1 + 3 + 0 + 5 + 1).

It is not an unprimeable number, because it can be changed into a prime (81813091) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1515030 + ... + 1515083.

It is an arithmetic number, because the mean of its divisors is an integer number (15150570).

Almost surely, 2^81813051 is an apocalyptic number.

81813051 is a deficient number, since it is larger than the sum of its proper divisors (39391509).

81813051 is a wasteful number, since it uses less digits than its factorization.

81813051 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3030122 (or 3030116 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 27.

The square root of 81813051 is about 9045.0567162401. The cubic root of 81813051 is about 434.1177361845.

Adding to 81813051 its reverse (15031818), we get a palindrome (96844869).

The spelling of 81813051 in words is "eighty-one million, eight hundred thirteen thousand, fifty-one".