1656989 has 4 divisors (see below), whose sum is σ = 1729056. Its totient is φ = 1584924.

The previous prime is 1656979. The next prime is 1656997. The reversal of 1656989 is 9896561.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 9896561 = 1549 ⋅6389.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1656989 is a prime.

It is a super-2 number, since 2×1656989² = 5491225092242, which contains 22 as substring.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1656979) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 35999 + ... + 36044.

It is an arithmetic number, because the mean of its divisors is an integer number (432264).

2^1656989 is an apocalyptic number.

It is an amenable number.

1656989 is a deficient number, since it is larger than the sum of its proper divisors (72067).

1656989 is an equidigital number, since it uses as much as digits as its factorization.

1656989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72066.

The product of its digits is 116640, while the sum is 44.

The square root of 1656989 is about 1287.2408477049. The cubic root of 1656989 is about 118.3331816877. Note that the first 3 decimals are identical.

The spelling of 1656989 in words is "one million, six hundred fifty-six thousand, nine hundred eighty-nine".