2128649 has 2 divisors, whose sum is σ = 2128650. Its totient is φ = 2128648.

The previous prime is 2128631. The next prime is 2128663. The reversal of 2128649 is 9468212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1729225 + 399424 = 1315^2 + 632^2 .

It is a cyclic number.

It is not a de Polignac number, because 2128649 - 2¹² = 2124553 is a prime.

It is a super-2 number, since 2×2128649² = 9062293130402, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (2128669) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1064324 + 1064325.

It is an arithmetic number, because the mean of its divisors is an integer number (1064325).

2^2128649 is an apocalyptic number.

It is an amenable number.

2128649 is a deficient number, since it is larger than the sum of its proper divisors (1).

2128649 is an equidigital number, since it uses as much as digits as its factorization.

2128649 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6912, while the sum is 32.

The square root of 2128649 is about 1458.9890335434. The cubic root of 2128649 is about 128.6376265220.

Adding to 2128649 its sum of digits (32), we get a square (2128681 = 1459²).

The spelling of 2128649 in words is "two million, one hundred twenty-eight thousand, six hundred forty-nine".