77384921 has 4 divisors (see below), whose sum is σ = 77812644. Its totient is φ = 76957200.

The previous prime is 77384893. The next prime is 77384927. The reversal of 77384921 is 12948377.

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 34351321 + 43033600 = 5861^2 + 6560^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-77384921 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (77384927) 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, 213590 + ... + 213951.

It is an arithmetic number, because the mean of its divisors is an integer number (19453161).

Almost surely, 2^77384921 is an apocalyptic number.

It is an amenable number.

77384921 is a deficient number, since it is larger than the sum of its proper divisors (427723).

77384921 is a wasteful number, since it uses less digits than its factorization.

77384921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 427722.

The product of its digits is 84672, while the sum is 41.

The square root of 77384921 is about 8796.8699547055. The cubic root of 77384921 is about 426.1398164938.

The spelling of 77384921 in words is "seventy-seven million, three hundred eighty-four thousand, nine hundred twenty-one".