77699521 has 4 divisors (see below), whose sum is σ = 78763972. Its totient is φ = 76635072.

The previous prime is 77699513. The next prime is 77699527. The reversal of 77699521 is 12599677.

It is a happy number.

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 51279921 + 26419600 = 7161^2 + 5140^2 .

It is a cyclic number.

It is not a de Polignac number, because 77699521 - 2³ = 77699513 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (77699527) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 532116 + ... + 532261.

It is an arithmetic number, because the mean of its divisors is an integer number (19690993).

Almost surely, 2^77699521 is an apocalyptic number.

It is an amenable number.

77699521 is a deficient number, since it is larger than the sum of its proper divisors (1064451).

77699521 is a wasteful number, since it uses less digits than its factorization.

77699521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1064450.

The product of its digits is 238140, while the sum is 46.

The square root of 77699521 is about 8814.7331780378. The cubic root of 77699521 is about 426.7165107649.

The spelling of 77699521 in words is "seventy-seven million, six hundred ninety-nine thousand, five hundred twenty-one".