1285821 has 8 divisors (see below), whose sum is σ = 1904960. Its totient is φ = 857196.

The previous prime is 1285813. The next prime is 1285841.

1285821 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 1285821 - 2³ = 1285813 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 47623 = 1285821 / (1 + 2 + 8 + 5 + 8 + 2 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1285811) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23785 + ... + 23838.

It is an arithmetic number, because the mean of its divisors is an integer number (238120).

2^1285821 is an apocalyptic number.

It is an amenable number.

1285821 is a deficient number, since it is larger than the sum of its proper divisors (619139).

1285821 is an equidigital number, since it uses as much as digits as its factorization.

1285821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47632 (or 47626 counting only the distinct ones).

The product of its digits is 1280, while the sum is 27.

The square root of 1285821 is about 1133.9404746282. The cubic root of 1285821 is about 108.7410456361.

The spelling of 1285821 in words is "one million, two hundred eighty-five thousand, eight hundred twenty-one".