777777640 has 16 divisors (see below), whose sum is σ = 1749999780. Its totient is φ = 311111040.

The previous prime is 777777577. The next prime is 777777641. The reversal of 777777640 is 46777777.

It can be written as a sum of positive squares in 2 ways, for example, as 728244196 + 49533444 = 26986^2 + 7038^2 .

It is a nialpdrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (777777641) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9722181 + ... + 9722260.

Almost surely, 2^777777640 is an apocalyptic number.

It is an amenable number.

777777640 is an abundant number, since it is smaller than the sum of its proper divisors (972222140).

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

777777640 is a wasteful number, since it uses less digits than its factorization.

777777640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19444452 (or 19444448 counting only the distinct ones).

The product of its (nonzero) digits is 2823576, while the sum is 52.

The square root of 777777640 is about 27888.6650809966. The cubic root of 777777640 is about 919.6413378244.

The spelling of 777777640 in words is "seven hundred seventy-seven million, seven hundred seventy-seven thousand, six hundred forty".