10388991 has 16 divisors (see below), whose sum is σ = 14739200. Its totient is φ = 6490368.

The previous prime is 10388957. The next prime is 10388993. The reversal of 10388991 is 19988301.

It is a happy number.

It is not a de Polignac number, because 10388991 - 2⁷ = 10388863 is a prime.

It is a super-4 number, since 4×10388991⁴ (a number of 29 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (10388993) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4590 + ... + 6468.

It is an arithmetic number, because the mean of its divisors is an integer number (921200).

Almost surely, 2^10388991 is an apocalyptic number.

10388991 is a deficient number, since it is larger than the sum of its proper divisors (4350209).

10388991 is a wasteful number, since it uses less digits than its factorization.

10388991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1998.

The product of its (nonzero) digits is 15552, while the sum is 39.

The square root of 10388991 is about 3223.1957743829. The cubic root of 10388991 is about 218.2015292640.

The spelling of 10388991 in words is "ten million, three hundred eighty-eight thousand, nine hundred ninety-one".