77978573 has 4 divisors (see below), whose sum is σ = 80086140. Its totient is φ = 75871008.

The previous prime is 77978569. The next prime is 77978587. The reversal of 77978573 is 37587977.

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

It can be written as a sum of positive squares in 2 ways, for example, as 33849124 + 44129449 = 5818^2 + 6643^2 .

It is a cyclic number.

It is not a de Polignac number, because 77978573 - 2² = 77978569 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77978503) 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, 1053728 + ... + 1053801.

It is an arithmetic number, because the mean of its divisors is an integer number (20021535).

Almost surely, 2^77978573 is an apocalyptic number.

It is an amenable number.

77978573 is a deficient number, since it is larger than the sum of its proper divisors (2107567).

77978573 is a wasteful number, since it uses less digits than its factorization.

77978573 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2107566.

The product of its digits is 2593080, while the sum is 53.

The square root of 77978573 is about 8830.5477180071. The cubic root of 77978573 is about 427.2267405450.

The spelling of 77978573 in words is "seventy-seven million, nine hundred seventy-eight thousand, five hundred seventy-three".