780021 has 12 divisors (see below), whose sum is σ = 1229280. Its totient is φ = 472680.

The previous prime is 779993. The next prime is 780029. The reversal of 780021 is 120087.

It is not a de Polignac number, because 780021 - 2¹⁸ = 517877 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 779976 and 780003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (780029) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3841 + ... + 4038.

It is an arithmetic number, because the mean of its divisors is an integer number (102440).

2⁷⁸⁰⁰²¹ is an apocalyptic number.

It is an amenable number.

780021 is a deficient number, since it is larger than the sum of its proper divisors (449259).

780021 is a wasteful number, since it uses less digits than its factorization.

780021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7896 (or 7893 counting only the distinct ones).

The product of its (nonzero) digits is 112, while the sum is 18.

The square root of 780021 is about 883.1879754616. The cubic root of 780021 is about 92.0524669222.

The spelling of 780021 in words is "seven hundred eighty thousand, twenty-one".