821387 has 6 divisors (see below), whose sum is σ = 955548. Its totient is φ = 704004.

The previous prime is 821383. The next prime is 821411. The reversal of 821387 is 783128.

It is not a de Polignac number, because 821387 - 2² = 821383 is a prime.

It is a Duffinian number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 821387.

It is not an unprimeable number, because it can be changed into a prime (821383) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 8333 + ... + 8430.

It is an arithmetic number, because the mean of its divisors is an integer number (159258).

2⁸²¹³⁸⁷ is an apocalyptic number.

821387 is a deficient number, since it is larger than the sum of its proper divisors (134161).

821387 is a wasteful number, since it uses less digits than its factorization.

821387 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16777 (or 16770 counting only the distinct ones).

The product of its digits is 2688, while the sum is 29.

The square root of 821387 is about 906.3040328720. The cubic root of 821387 is about 93.6517596086.

The spelling of 821387 in words is "eight hundred twenty-one thousand, three hundred eighty-seven".