77775840 has 72 divisors (see below), whose sum is σ = 265414968. Its totient is φ = 20739840.

The previous prime is 77775829. The next prime is 77775847. The reversal of 77775840 is 4857777.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (72).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77775847) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 25566 + ... + 28445.

It is an arithmetic number, because the mean of its divisors is an integer number (3686319).

Almost surely, 2^77775840 is an apocalyptic number.

It is an amenable number.

77775840 is an abundant number, since it is smaller than the sum of its proper divisors (187639128).

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

77775840 is a wasteful number, since it uses less digits than its factorization.

77775840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54032 (or 54021 counting only the distinct ones).

The product of its (nonzero) digits is 384160, while the sum is 45.

The square root of 77775840 is about 8819.0611745242. The cubic root of 77775840 is about 426.8561766647.

The spelling of 77775840 in words is "seventy-seven million, seven hundred seventy-five thousand, eight hundred forty".