1656649 has 2 divisors, whose sum is σ = 1656650. Its totient is φ = 1656648.

The previous prime is 1656647. The next prime is 1656659. The reversal of 1656649 is 9466561.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1334025 + 322624 = 1155^2 + 568^2 .

It is a cyclic number.

It is not a de Polignac number, because 1656649 - 2¹ = 1656647 is a prime.

Together with 1656647, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1656647) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 828324 + 828325.

It is an arithmetic number, because the mean of its divisors is an integer number (828325).

2^1656649 is an apocalyptic number.

It is an amenable number.

1656649 is a deficient number, since it is larger than the sum of its proper divisors (1).

1656649 is an equidigital number, since it uses as much as digits as its factorization.

1656649 is an evil number, because the sum of its binary digits is even.

The product of its digits is 38880, while the sum is 37.

The square root of 1656649 is about 1287.1087755120. The cubic root of 1656649 is about 118.3250874811.

It can be divided in two parts, 16 and 56649, that added together give a palindrome (56665).

The spelling of 1656649 in words is "one million, six hundred fifty-six thousand, six hundred forty-nine".