77720771 has 4 divisors (see below), whose sum is σ = 78994944. Its totient is φ = 76446600.

The previous prime is 77720761. The next prime is 77720791. The reversal of 77720771 is 17702777.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-77720771 is a prime.

It is a super-5 number, since 5×77720771⁵ (a number of 41 digits) contains 55555 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (77720701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 636995 + ... + 637116.

It is an arithmetic number, because the mean of its divisors is an integer number (19748736).

Almost surely, 2^77720771 is an apocalyptic number.

77720771 is a deficient number, since it is larger than the sum of its proper divisors (1274173).

77720771 is a wasteful number, since it uses less digits than its factorization.

77720771 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1274172.

The product of its (nonzero) digits is 33614, while the sum is 38.

The square root of 77720771 is about 8815.9384639413. The cubic root of 77720771 is about 426.7554080417.

The spelling of 77720771 in words is "seventy-seven million, seven hundred twenty thousand, seven hundred seventy-one".