81670019 has 2 divisors, whose sum is σ = 81670020. Its totient is φ = 81670018.

The previous prime is 81670007. The next prime is 81670031. The reversal of 81670019 is 91007618.

It is a balanced prime because it is at equal distance from previous prime (81670007) and next prime (81670031).

It is a cyclic number.

It is not a de Polignac number, because 81670019 - 2¹² = 81665923 is a prime.

It is a super-2 number, since 2×81670019² = 13339984006920722, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is equal to p_4761293 and since 81670019 and 4761293 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (81670619) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40835009 + 40835010.

It is an arithmetic number, because the mean of its divisors is an integer number (40835010).

Almost surely, 2^81670019 is an apocalyptic number.

81670019 is a deficient number, since it is larger than the sum of its proper divisors (1).

81670019 is an equidigital number, since it uses as much as digits as its factorization.

81670019 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3024, while the sum is 32.

The square root of 81670019 is about 9037.1466182640. The cubic root of 81670019 is about 433.8646023727.

The spelling of 81670019 in words is "eighty-one million, six hundred seventy thousand, nineteen".