77984640 has 128 divisors (see below), whose sum is σ = 276256800. Its totient is φ = 20791296.

The previous prime is 77984597. The next prime is 77984653. The reversal of 77984640 is 4648977.

It is a tau number, because it is divible by the number of its divisors (128).

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15024 + ... + 19536.

Almost surely, 2^77984640 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 77984640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (138128400).

77984640 is an abundant number, since it is smaller than the sum of its proper divisors (198272160).

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

77984640 is a wasteful number, since it uses less digits than its factorization.

77984640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4541 (or 4523 counting only the distinct ones).

The product of its (nonzero) digits is 338688, while the sum is 45.

The square root of 77984640 is about 8830.8912347509. The cubic root of 77984640 is about 427.2378201588.

The spelling of 77984640 in words is "seventy-seven million, nine hundred eighty-four thousand, six hundred forty".