1640929 has 2 divisors, whose sum is σ = 1640930. Its totient is φ = 1640928.

The previous prime is 1640927. The next prime is 1640939. The reversal of 1640929 is 9290461.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1221025 + 419904 = 1105^2 + 648^2 .

It is an emirp because it is prime and its reverse (9290461) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1640929 - 2¹ = 1640927 is a prime.

Together with 1640927, it forms a pair of twin primes.

It is a Chen prime.

1640929 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 1640929.

It is not a weakly prime, because it can be changed into another prime (1640927) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 820464 + 820465.

It is an arithmetic number, because the mean of its divisors is an integer number (820465).

2^1640929 is an apocalyptic number.

It is an amenable number.

1640929 is a deficient number, since it is larger than the sum of its proper divisors (1).

1640929 is an equidigital number, since it uses as much as digits as its factorization.

1640929 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3888, while the sum is 31.

The square root of 1640929 is about 1280.9875096971. The cubic root of 1640929 is about 117.9496337766.

The spelling of 1640929 in words is "one million, six hundred forty thousand, nine hundred twenty-nine".