77681021 has 8 divisors (see below), whose sum is σ = 84806784. Its totient is φ = 70565920.

The previous prime is 77681017. The next prime is 77681027. The reversal of 77681021 is 12018677.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 77681021 - 2² = 77681017 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77681027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 26585 + ... + 29361.

It is an arithmetic number, because the mean of its divisors is an integer number (10600848).

Almost surely, 2^77681021 is an apocalyptic number.

It is an amenable number.

77681021 is a deficient number, since it is larger than the sum of its proper divisors (7125763).

77681021 is a wasteful number, since it uses less digits than its factorization.

77681021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5331.

The product of its (nonzero) digits is 4704, while the sum is 32.

The square root of 77681021 is about 8813.6837361004. The cubic root of 77681021 is about 426.6826414782.

Adding to 77681021 its reverse (12018677), we get a palindrome (89699698).

The spelling of 77681021 in words is "seventy-seven million, six hundred eighty-one thousand, twenty-one".