780828257 has 4 divisors (see below), whose sum is σ = 851812656. Its totient is φ = 709843860.

The previous prime is 780828253. The next prime is 780828259. The reversal of 780828257 is 752828087.

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 not a de Polignac number, because 780828257 - 2² = 780828253 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (780828253) 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, 35492183 + ... + 35492204.

It is an arithmetic number, because the mean of its divisors is an integer number (212953164).

Almost surely, 2^780828257 is an apocalyptic number.

It is an amenable number.

780828257 is a deficient number, since it is larger than the sum of its proper divisors (70984399).

780828257 is a wasteful number, since it uses less digits than its factorization.

780828257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70984398.

The product of its (nonzero) digits is 501760, while the sum is 47.

The square root of 780828257 is about 27943.3043321652. The cubic root of 780828257 is about 920.8421152829.

The spelling of 780828257 in words is "seven hundred eighty million, eight hundred twenty-eight thousand, two hundred fifty-seven".