1236021 has 4 divisors (see below), whose sum is σ = 1648032. Its totient is φ = 824012.

The previous prime is 1236017. The next prime is 1236073. The reversal of 1236021 is 1206321.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1206321 = 3 ⋅402107.

It is a cyclic number.

It is not a de Polignac number, because 1236021 - 2² = 1236017 is a prime.

It is a D-number.

1236021 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1235021) 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 3 ways as a sum of consecutive naturals, for example, 206001 + ... + 206006.

It is an arithmetic number, because the mean of its divisors is an integer number (412008).

2^1236021 is an apocalyptic number.

It is an amenable number.

1236021 is a deficient number, since it is larger than the sum of its proper divisors (412011).

1236021 is an equidigital number, since it uses as much as digits as its factorization.

1236021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 412010.

The product of its (nonzero) digits is 72, while the sum is 15.

The square root of 1236021 is about 1111.7648132586. The cubic root of 1236021 is about 107.3186703304.

It can be divided in two parts, 12360 and 21, that multiplied together give a triangular number (259560 = T₇₂₀).

The spelling of 1236021 in words is "one million, two hundred thirty-six thousand, twenty-one".