106651991 has 2 divisors, whose sum is σ = 106651992. Its totient is φ = 106651990.

The previous prime is 106651981. The next prime is 106652003. The reversal of 106651991 is 199156601.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 106651991 - 2⁶ = 106651927 is a prime.

It is a super-2 number, since 2×106651991² = 22749294368528162, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (106651981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 53325995 + 53325996.

It is an arithmetic number, because the mean of its divisors is an integer number (53325996).

Almost surely, 2^106651991 is an apocalyptic number.

106651991 is a deficient number, since it is larger than the sum of its proper divisors (1).

106651991 is an equidigital number, since it uses as much as digits as its factorization.

106651991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 14580, while the sum is 38.

The square root of 106651991 is about 10327.2450827895. The cubic root of 106651991 is about 474.2306896926.

The spelling of 106651991 in words is "one hundred six million, six hundred fifty-one thousand, nine hundred ninety-one".