81640151 has 2 divisors, whose sum is σ = 81640152. Its totient is φ = 81640150.

The previous prime is 81640099. The next prime is 81640159. The reversal of 81640151 is 15104618.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81640151 - 2¹⁴ = 81623767 is a prime.

It is a super-2 number, since 2×81640151² = 13330228510605602, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 81640151.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81640159) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40820075 + 40820076.

It is an arithmetic number, because the mean of its divisors is an integer number (40820076).

Almost surely, 2^81640151 is an apocalyptic number.

81640151 is a deficient number, since it is larger than the sum of its proper divisors (1).

81640151 is an equidigital number, since it uses as much as digits as its factorization.

81640151 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 960, while the sum is 26.

The square root of 81640151 is about 9035.4939544001. The cubic root of 81640151 is about 433.8117055727.

Adding to 81640151 its reverse (15104618), we get a palindrome (96744769).

The spelling of 81640151 in words is "eighty-one million, six hundred forty thousand, one hundred fifty-one".