77820480 has 112 divisors (see below), whose sum is σ = 274563840. Its totient is φ = 20749824.

The previous prime is 77820461. The next prime is 77820487. The reversal of 77820480 is 8402877.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (77820487) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4137 + ... + 13143.

Almost surely, 2^77820480 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 77820480, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (137281920).

77820480 is an abundant number, since it is smaller than the sum of its proper divisors (196743360).

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

77820480 is a wasteful number, since it uses less digits than its factorization.

77820480 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9033 (or 9017 counting only the distinct ones).

The product of its (nonzero) digits is 25088, while the sum is 36.

The square root of 77820480 is about 8821.5916931130. The cubic root of 77820480 is about 426.9378267647.

The spelling of 77820480 in words is "seventy-seven million, eight hundred twenty thousand, four hundred eighty".