1640761 has 2 divisors, whose sum is σ = 1640762. Its totient is φ = 1640760.

The previous prime is 1640753. The next prime is 1640773. The reversal of 1640761 is 1670461.

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., 1115136 + 525625 = 1056^2 + 725^2 .

It is a cyclic number.

It is not a de Polignac number, because 1640761 - 2³ = 1640753 is a prime.

1640761 is a lucky number.

It is not a weakly prime, because it can be changed into another prime (1640701) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 820380 + 820381.

It is an arithmetic number, because the mean of its divisors is an integer number (820381).

2^1640761 is an apocalyptic number.

It is an amenable number.

1640761 is a deficient number, since it is larger than the sum of its proper divisors (1).

1640761 is an equidigital number, since it uses as much as digits as its factorization.

1640761 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1008, while the sum is 25.

The square root of 1640761 is about 1280.9219336088. The cubic root of 1640761 is about 117.9456083709.

It can be divided in two parts, 1640 and 761, that added together give a 4-th power (2401 = 7⁴).

The spelling of 1640761 in words is "one million, six hundred forty thousand, seven hundred sixty-one".