778745321 has 4 divisors (see below), whose sum is σ = 781848144. Its totient is φ = 775642500.

The previous prime is 778745309. The next prime is 778745347. The reversal of 778745321 is 123547877.

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 778745321 - 2⁶ = 778745257 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (778745921) 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, 1551035 + ... + 1551536.

It is an arithmetic number, because the mean of its divisors is an integer number (195462036).

Almost surely, 2^778745321 is an apocalyptic number.

It is an amenable number.

778745321 is a deficient number, since it is larger than the sum of its proper divisors (3102823).

778745321 is a wasteful number, since it uses less digits than its factorization.

778745321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3102822.

The product of its digits is 329280, while the sum is 44.

The square root of 778745321 is about 27906.0086898861. The cubic root of 778745321 is about 920.0225738790.

The spelling of 778745321 in words is "seven hundred seventy-eight million, seven hundred forty-five thousand, three hundred twenty-one".