105009991 has 2 divisors, whose sum is σ = 105009992. Its totient is φ = 105009990.

The previous prime is 105009953. The next prime is 105009997. The reversal of 105009991 is 199900501.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-105009991 is a prime.

It is a super-2 number, since 2×105009991² = 22054196419640162, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (105009997) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 52504995 + 52504996.

It is an arithmetic number, because the mean of its divisors is an integer number (52504996).

Almost surely, 2^105009991 is an apocalyptic number.

105009991 is a deficient number, since it is larger than the sum of its proper divisors (1).

105009991 is an equidigital number, since it uses as much as digits as its factorization.

105009991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3645, while the sum is 34.

The square root of 105009991 is about 10247.4382652446. The cubic root of 105009991 is about 471.7843608842.

The spelling of 105009991 in words is "one hundred five million, nine thousand, nine hundred ninety-one".