77213809 has 4 divisors (see below), whose sum is σ = 78856704. Its totient is φ = 75570916.

The previous prime is 77213803. The next prime is 77213827. The reversal of 77213809 is 90831277.

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 77213809 - 2¹⁷ = 77082737 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (77213803) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 821377 + ... + 821470.

It is an arithmetic number, because the mean of its divisors is an integer number (19714176).

Almost surely, 2^77213809 is an apocalyptic number.

It is an amenable number.

77213809 is a deficient number, since it is larger than the sum of its proper divisors (1642895).

77213809 is a wasteful number, since it uses less digits than its factorization.

77213809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1642894.

The product of its (nonzero) digits is 21168, while the sum is 37.

The square root of 77213809 is about 8787.1388403735. The cubic root of 77213809 is about 425.8254940731.

The spelling of 77213809 in words is "seventy-seven million, two hundred thirteen thousand, eight hundred nine".