77021780 has 48 divisors (see below), whose sum is σ = 180774720. Its totient is φ = 27321600.

The previous prime is 77021771. The next prime is 77021831. The reversal of 77021780 is 8712077.

77021780 is nontrivially palindromic in base 14.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4751 + ... + 13289.

It is an arithmetic number, because the mean of its divisors is an integer number (3766140).

Almost surely, 2^77021780 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 77021780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (90387360).

77021780 is an abundant number, since it is smaller than the sum of its proper divisors (103752940).

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

77021780 is a wasteful number, since it uses less digits than its factorization.

77021780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8600 (or 8598 counting only the distinct ones).

The product of its (nonzero) digits is 5488, while the sum is 32.

The square root of 77021780 is about 8776.2053303236. The cubic root of 77021780 is about 425.4721948982.

The spelling of 77021780 in words is "seventy-seven million, twenty-one thousand, seven hundred eighty".