8991657 has 18 divisors (see below), whose sum is σ = 13800878. Its totient is φ = 5640192.

The previous prime is 8991649. The next prime is 8991667. The reversal of 8991657 is 7561998.

8991657 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 3 ways, for example, as 1089936 + 7901721 = 1044^2 + 2811^2 .

It is not a de Polignac number, because 8991657 - 2³ = 8991649 is a prime.

It is a Duffinian number.

8991657 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (8991607) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 873 + ... + 4329.

Almost surely, 2^8991657 is an apocalyptic number.

It is an amenable number.

8991657 is a deficient number, since it is larger than the sum of its proper divisors (4809221).

8991657 is a wasteful number, since it uses less digits than its factorization.

8991657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3497 (or 3477 counting only the distinct ones).

The product of its digits is 136080, while the sum is 45.

The square root of 8991657 is about 2998.6091776022. The cubic root of 8991657 is about 207.9440878440.

It can be divided in two parts, 899 and 1657, that added together give a triangular number (2556 = T₇₁).

The spelling of 8991657 in words is "eight million, nine hundred ninety-one thousand, six hundred fifty-seven".