106021991 has 2 divisors, whose sum is σ = 106021992. Its totient is φ = 106021990.

The previous prime is 106021987. The next prime is 106022039. The reversal of 106021991 is 199120601.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 106021991 - 2² = 106021987 is a prime.

It is a super-2 number, since 2×106021991² = 22481325151208162, which contains 22 as substring.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (106021901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 53010995 + 53010996.

It is an arithmetic number, because the mean of its divisors is an integer number (53010996).

Almost surely, 2^106021991 is an apocalyptic number.

106021991 is a deficient number, since it is larger than the sum of its proper divisors (1).

106021991 is an equidigital number, since it uses as much as digits as its factorization.

106021991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 972, while the sum is 29.

The square root of 106021991 is about 10296.6980629714. The cubic root of 106021991 is about 473.2950748795.

The spelling of 106021991 in words is "one hundred six million, twenty-one thousand, nine hundred ninety-one".