1356021 has 10 divisors (see below), whose sum is σ = 2025782. Its totient is φ = 903960.

The previous prime is 1356007. The next prime is 1356037. The reversal of 1356021 is 1206531.

It can be written as a sum of positive squares in only one way, i.e., 1347921 + 8100 = 1161^2 + 90^2 .

It is not a de Polignac number, because 1356021 - 2⁵ = 1355989 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1355985 and 1356003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1356221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 8290 + ... + 8451.

2^1356021 is an apocalyptic number.

It is an amenable number.

1356021 is a deficient number, since it is larger than the sum of its proper divisors (669761).

1356021 is an equidigital number, since it uses as much as digits as its factorization.

1356021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16753 (or 16744 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 18.

The square root of 1356021 is about 1164.4831471516. The cubic root of 1356021 is about 110.6850090966.

The spelling of 1356021 in words is "one million, three hundred fifty-six thousand, twenty-one".