77490640 has 40 divisors (see below), whose sum is σ = 180914760. Its totient is φ = 30867456.

The previous prime is 77490631. The next prime is 77490649. The reversal of 77490640 is 4609477.

It is an interprime number because it is at equal distance from previous prime (77490631) and next prime (77490649).

It can be written as a sum of positive squares in 4 ways, for example, as 42302016 + 35188624 = 6504^2 + 5932^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a self number, because there is not a number n which added to its sum of digits gives 77490640.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77490649) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18676 + ... + 22444.

It is an arithmetic number, because the mean of its divisors is an integer number (4522869).

Almost surely, 2^77490640 is an apocalyptic number.

It is an amenable number.

77490640 is an abundant number, since it is smaller than the sum of its proper divisors (103424120).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

77490640 is a wasteful number, since it uses less digits than its factorization.

77490640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4039 (or 4033 counting only the distinct ones).

The product of its (nonzero) digits is 42336, while the sum is 37.

The square root of 77490640 is about 8802.8768025004. The cubic root of 77490640 is about 426.3337844090. Note that the first 3 decimals are identical.

The spelling of 77490640 in words is "seventy-seven million, four hundred ninety thousand, six hundred forty".