1009991656 has 32 divisors (see below), whose sum is σ = 1956787200. Its totient is φ = 488214720.

The previous prime is 1009991629. The next prime is 1009991659. The reversal of 1009991656 is 6561999001.

It is not an unprimeable number, because it can be changed into a prime (1009991659) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 422641 + ... + 425023.

It is an arithmetic number, because the mean of its divisors is an integer number (61149600).

Almost surely, 2^1009991656 is an apocalyptic number.

It is an amenable number.

1009991656 is a deficient number, since it is larger than the sum of its proper divisors (946795544).

1009991656 is a wasteful number, since it uses less digits than its factorization.

1009991656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4129 (or 4125 counting only the distinct ones).

The product of its (nonzero) digits is 131220, while the sum is 46.

The square root of 1009991656 is about 31780.3658883909. The cubic root of 1009991656 is about 1003.3195205902.

The spelling of 1009991656 in words is "one billion, nine million, nine hundred ninety-one thousand, six hundred fifty-six".