10501991 has 2 divisors, whose sum is σ = 10501992. Its totient is φ = 10501990.

The previous prime is 10501987. The next prime is 10501993. The reversal of 10501991 is 19910501.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 10501991 - 2² = 10501987 is a prime.

It is a super-2 number, since 2×10501991² = 220583629928162, which contains 22 as substring.

Together with 10501993, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 10501991.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (10501993) 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, 5250995 + 5250996.

It is an arithmetic number, because the mean of its divisors is an integer number (5250996).

Almost surely, 2^10501991 is an apocalyptic number.

10501991 is a deficient number, since it is larger than the sum of its proper divisors (1).

10501991 is an equidigital number, since it uses as much as digits as its factorization.

10501991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 405, while the sum is 26.

The square root of 10501991 is about 3240.6775526115. The cubic root of 10501991 is about 218.9897967905.

The spelling of 10501991 in words is "ten million, five hundred one thousand, nine hundred ninety-one".