10639991 has 4 divisors (see below), whose sum is σ = 10657800. Its totient is φ = 10622184.

The previous prime is 10639987. The next prime is 10640009. The reversal of 10639991 is 19993601.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 10639991 - 2² = 10639987 is a prime.

It is a super-2 number, since 2×10639991² = 226418816960162, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (10639921) 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 in 3 ways as a sum of consecutive naturals, for example, 7976 + ... + 9213.

It is an arithmetic number, because the mean of its divisors is an integer number (2664450).

Almost surely, 2^10639991 is an apocalyptic number.

10639991 is a deficient number, since it is larger than the sum of its proper divisors (17809).

10639991 is an equidigital number, since it uses as much as digits as its factorization.

10639991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17808.

The product of its (nonzero) digits is 13122, while the sum is 38.

The square root of 10639991 is about 3261.8999064962. The cubic root of 10639991 is about 219.9448277627.

The spelling of 10639991 in words is "ten million, six hundred thirty-nine thousand, nine hundred ninety-one".