780828921 has 72 divisors (see below), whose sum is σ = 1285244064. Its totient is φ = 455051520.

The previous prime is 780828911. The next prime is 780828941. The reversal of 780828921 is 129828087.

It is a happy number.

It is not a de Polignac number, because 780828921 - 2⁷ = 780828793 is a prime.

It is not an unprimeable number, because it can be changed into a prime (780828911) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 3700506 + ... + 3700716.

It is an arithmetic number, because the mean of its divisors is an integer number (17850612).

Almost surely, 2^780828921 is an apocalyptic number.

It is an amenable number.

780828921 is a deficient number, since it is larger than the sum of its proper divisors (504415143).

780828921 is a wasteful number, since it uses less digits than its factorization.

780828921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 339 (or 317 counting only the distinct ones).

The product of its (nonzero) digits is 129024, while the sum is 45.

The square root of 780828921 is about 27943.3162133631. The cubic root of 780828921 is about 920.8423763044.

The spelling of 780828921 in words is "seven hundred eighty million, eight hundred twenty-eight thousand, nine hundred twenty-one".