77321681 has 4 divisors (see below), whose sum is σ = 77474100. Its totient is φ = 77169264.

The previous prime is 77321677. The next prime is 77321711. The reversal of 77321681 is 18612377.

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 61481281 + 15840400 = 7841^2 + 3980^2 .

It is a cyclic number.

It is not a de Polignac number, because 77321681 - 2² = 77321677 is a prime.

It is a super-2 number, since 2×77321681² = 11957284705331522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (77321641) 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, 75446 + ... + 76463.

It is an arithmetic number, because the mean of its divisors is an integer number (19368525).

Almost surely, 2^77321681 is an apocalyptic number.

It is an amenable number.

77321681 is a deficient number, since it is larger than the sum of its proper divisors (152419).

77321681 is a wasteful number, since it uses less digits than its factorization.

77321681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 152418.

The product of its digits is 14112, while the sum is 35.

The square root of 77321681 is about 8793.2747597240. The cubic root of 77321681 is about 426.0237024584.

The spelling of 77321681 in words is "seventy-seven million, three hundred twenty-one thousand, six hundred eighty-one".