10991639 has 8 divisors (see below), whose sum is σ = 12014208. Its totient is φ = 10010880.

The previous prime is 10991611. The next prime is 10991653. The reversal of 10991639 is 93619901.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-10991639 is a prime.

It is a super-2 number, since 2×10991639² = 241632255812642, 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 (10991699) 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 7 ways as a sum of consecutive naturals, for example, 9902 + ... + 10955.

It is an arithmetic number, because the mean of its divisors is an integer number (1501776).

Almost surely, 2^10991639 is an apocalyptic number.

10991639 is a deficient number, since it is larger than the sum of its proper divisors (1022569).

10991639 is a wasteful number, since it uses less digits than its factorization.

10991639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20905.

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

The square root of 10991639 is about 3315.3640825707. The cubic root of 10991639 is about 222.3416472062.

The spelling of 10991639 in words is "ten million, nine hundred ninety-one thousand, six hundred thirty-nine".