77720500 has 96 divisors (see below), whose sum is σ = 199600128. Its totient is φ = 26064000.

The previous prime is 77720497. The next prime is 77720501. The reversal of 77720500 is 502777.

It is a happy number.

It is a super-2 number, since 2×77720500² = 12080952240500000, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77720501) 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, 70957 + ... + 72043.

It is an arithmetic number, because the mean of its divisors is an integer number (2079168).

Almost surely, 2^77720500 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 77720500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (99800064).

77720500 is an abundant number, since it is smaller than the sum of its proper divisors (121879628).

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

77720500 is a wasteful number, since it uses less digits than its factorization.

77720500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1130 (or 1118 counting only the distinct ones).

The product of its (nonzero) digits is 3430, while the sum is 28.

The square root of 77720500 is about 8815.9230940384. The cubic root of 77720500 is about 426.7549120317.

The spelling of 77720500 in words is "seventy-seven million, seven hundred twenty thousand, five hundred".