81209707 has 2 divisors, whose sum is σ = 81209708. Its totient is φ = 81209706.

The previous prime is 81209701. The next prime is 81209717. The reversal of 81209707 is 70790218.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81209707 is a prime.

It is a super-2 number, since 2×81209707² = 13190033022051698, which contains 22 as substring.

It is equal to p_4736059 and since 81209707 and 4736059 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 (81209701) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40604853 + 40604854.

It is an arithmetic number, because the mean of its divisors is an integer number (40604854).

Almost surely, 2^81209707 is an apocalyptic number.

81209707 is a deficient number, since it is larger than the sum of its proper divisors (1).

81209707 is an equidigital number, since it uses as much as digits as its factorization.

81209707 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7056, while the sum is 34.

The square root of 81209707 is about 9011.6428579921. The cubic root of 81209707 is about 433.0479441709.

The spelling of 81209707 in words is "eighty-one million, two hundred nine thousand, seven hundred seven".