77880421 has 4 divisors (see below), whose sum is σ = 77928012. Its totient is φ = 77832832.

The previous prime is 77880419. The next prime is 77880437. The reversal of 77880421 is 12408877.

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 49140100 + 28740321 = 7010^2 + 5361^2 .

It is a cyclic number.

It is not a de Polignac number, because 77880421 - 2¹ = 77880419 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 (77880521) 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, 21250 + ... + 24643.

It is an arithmetic number, because the mean of its divisors is an integer number (19482003).

Almost surely, 2^77880421 is an apocalyptic number.

It is an amenable number.

77880421 is a deficient number, since it is larger than the sum of its proper divisors (47591).

77880421 is a wasteful number, since it uses less digits than its factorization.

77880421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47590.

The product of its (nonzero) digits is 25088, while the sum is 37.

The square root of 77880421 is about 8824.9884419188. The cubic root of 77880421 is about 427.0474145090.

The spelling of 77880421 in words is "seventy-seven million, eight hundred eighty thousand, four hundred twenty-one".