81633151 has 2 divisors, whose sum is σ = 81633152. Its totient is φ = 81633150.

The previous prime is 81633143. The next prime is 81633193. The reversal of 81633151 is 15133618.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81633151 - 2³ = 81633143 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81633131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40816575 + 40816576.

It is an arithmetic number, because the mean of its divisors is an integer number (40816576).

Almost surely, 2^81633151 is an apocalyptic number.

81633151 is a deficient number, since it is larger than the sum of its proper divisors (1).

81633151 is an equidigital number, since it uses as much as digits as its factorization.

81633151 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2160, while the sum is 28.

The square root of 81633151 is about 9035.1065848721. The cubic root of 81633151 is about 433.7993065725.

Adding to 81633151 its reverse (15133618), we get a palindrome (96766769).

The spelling of 81633151 in words is "eighty-one million, six hundred thirty-three thousand, one hundred fifty-one".