77955640 has 32 divisors (see below), whose sum is σ = 200458080. Its totient is φ = 26727552.

The previous prime is 77955629. The next prime is 77955641. The reversal of 77955640 is 4655977.

It is a Smith number, since the sum of its digits (43) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77955641) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 138927 + ... + 139486.

It is an arithmetic number, because the mean of its divisors is an integer number (6264315).

Almost surely, 2^77955640 is an apocalyptic number.

77955640 is a gapful number since it is divisible by the number (70) formed by its first and last digit.

It is an amenable number.

77955640 is an abundant number, since it is smaller than the sum of its proper divisors (122502440).

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

77955640 is a wasteful number, since it uses less digits than its factorization.

77955640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 278431 (or 278427 counting only the distinct ones).

The product of its (nonzero) digits is 264600, while the sum is 43.

The square root of 77955640 is about 8829.2491186963. The cubic root of 77955640 is about 427.1848548872.

The spelling of 77955640 in words is "seventy-seven million, nine hundred fifty-five thousand, six hundred forty".