77772121 has 16 divisors (see below), whose sum is σ = 91986048. Its totient is φ = 64368000.

The previous prime is 77772077. The next prime is 77772139. The reversal of 77772121 is 12127777.

It is a cyclic number.

It is not a de Polignac number, because 77772121 - 2¹³ = 77763929 is a prime.

It is not an unprimeable number, because it can be changed into a prime (77772151) 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 15 ways as a sum of consecutive naturals, for example, 27646 + ... + 30328.

It is an arithmetic number, because the mean of its divisors is an integer number (5749128).

Almost surely, 2^77772121 is an apocalyptic number.

It is an amenable number.

77772121 is a deficient number, since it is larger than the sum of its proper divisors (14213927).

77772121 is a wasteful number, since it uses less digits than its factorization.

77772121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2832.

The product of its digits is 9604, while the sum is 34.

The square root of 77772121 is about 8818.8503218957. The cubic root of 77772121 is about 426.8493729091.

Adding to 77772121 its reverse (12127777), we get a palindrome (89899898).

The spelling of 77772121 in words is "seventy-seven million, seven hundred seventy-two thousand, one hundred twenty-one".