77439421 has 4 divisors (see below), whose sum is σ = 81515200. Its totient is φ = 73363644.

The previous prime is 77439419. The next prime is 77439433. The reversal of 77439421 is 12493477.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 77439421 - 2¹ = 77439419 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 (77439491) 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, 2037861 + ... + 2037898.

It is an arithmetic number, because the mean of its divisors is an integer number (20378800).

Almost surely, 2^77439421 is an apocalyptic number.

It is an amenable number.

77439421 is a deficient number, since it is larger than the sum of its proper divisors (4075779).

77439421 is a wasteful number, since it uses less digits than its factorization.

77439421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4075778.

The product of its digits is 42336, while the sum is 37.

The square root of 77439421 is about 8799.9671022112. The cubic root of 77439421 is about 426.2398324042.

The spelling of 77439421 in words is "seventy-seven million, four hundred thirty-nine thousand, four hundred twenty-one".