77928145 has 4 divisors (see below), whose sum is σ = 93513780. Its totient is φ = 62342512.

The previous prime is 77928143. The next prime is 77928173. The reversal of 77928145 is 54182977.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 54182977 = 379 ⋅142963.

It can be written as a sum of positive squares in 2 ways, for example, as 8105409 + 69822736 = 2847^2 + 8356^2 .

It is a cyclic number.

It is not a de Polignac number, because 77928145 - 2¹ = 77928143 is a prime.

It is not an unprimeable number, because it can be changed into a prime (77928143) 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, 7792810 + ... + 7792819.

It is an arithmetic number, because the mean of its divisors is an integer number (23378445).

Almost surely, 2^77928145 is an apocalyptic number.

It is an amenable number.

77928145 is a deficient number, since it is larger than the sum of its proper divisors (15585635).

77928145 is a wasteful number, since it uses less digits than its factorization.

77928145 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15585634.

The product of its digits is 141120, while the sum is 43.

The square root of 77928145 is about 8827.6919407057. The cubic root of 77928145 is about 427.1346261985.

The spelling of 77928145 in words is "seventy-seven million, nine hundred twenty-eight thousand, one hundred forty-five".