77321820 has 24 divisors (see below), whose sum is σ = 216501264. Its totient is φ = 20619136.

The previous prime is 77321807. The next prime is 77321851. The reversal of 77321820 is 2812377.

It is a super-2 number, since 2×77321820² = 11957327696224800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 644289 + ... + 644408.

It is an arithmetic number, because the mean of its divisors is an integer number (9020886).

Almost surely, 2^77321820 is an apocalyptic number.

It is an amenable number.

77321820 is an abundant number, since it is smaller than the sum of its proper divisors (139179444).

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

77321820 is a wasteful number, since it uses less digits than its factorization.

77321820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1288709 (or 1288707 counting only the distinct ones).

The product of its (nonzero) digits is 4704, while the sum is 30.

The square root of 77321820 is about 8793.2826634881. The cubic root of 77321820 is about 426.0239577436.

The spelling of 77321820 in words is "seventy-seven million, three hundred twenty-one thousand, eight hundred twenty".