77205121 has 4 divisors (see below), whose sum is σ = 88234432. Its totient is φ = 66175812.

The previous prime is 77205119. The next prime is 77205131. The reversal of 77205121 is 12150277.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12150277 = 1487 ⋅8171.

It is a cyclic number.

It is not a de Polignac number, because 77205121 - 2¹ = 77205119 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (77205131) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5514645 + ... + 5514658.

It is an arithmetic number, because the mean of its divisors is an integer number (22058608).

Almost surely, 2^77205121 is an apocalyptic number.

It is an amenable number.

77205121 is a deficient number, since it is larger than the sum of its proper divisors (11029311).

77205121 is a wasteful number, since it uses less digits than its factorization.

77205121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11029310.

The product of its (nonzero) digits is 980, while the sum is 25.

The square root of 77205121 is about 8786.6444675997. The cubic root of 77205121 is about 425.8095223590.

Adding to 77205121 its reverse (12150277), we get a palindrome (89355398).

The spelling of 77205121 in words is "seventy-seven million, two hundred five thousand, one hundred twenty-one".