77145978 has 64 divisors (see below), whose sum is σ = 191036160. Its totient is φ = 20224512.

The previous prime is 77145977. The next prime is 77145997. The reversal of 77145978 is 87954177.

It is not an unprimeable number, because it can be changed into a prime (77145977) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 124726 + ... + 125342.

It is an arithmetic number, because the mean of its divisors is an integer number (2984940).

Almost surely, 2^77145978 is an apocalyptic number.

77145978 is a gapful number since it is divisible by the number (78) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 77145978, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (95518080).

77145978 is an abundant number, since it is smaller than the sum of its proper divisors (113890182).

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

77145978 is a wasteful number, since it uses less digits than its factorization.

77145978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 871.

The product of its digits is 493920, while the sum is 48.

The square root of 77145978 is about 8783.2783173483. The cubic root of 77145978 is about 425.7007640899.

The spelling of 77145978 in words is "seventy-seven million, one hundred forty-five thousand, nine hundred seventy-eight".