1206921 has 4 divisors (see below), whose sum is σ = 1609232. Its totient is φ = 804612.

The previous prime is 1206869. The next prime is 1206941. The reversal of 1206921 is 1296021.

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: 1296021 = 3 ⋅432007.

It is not a de Polignac number, because 1206921 - 2¹¹ = 1204873 is a prime.

It is a D-number.

It is a Duffinian number.

1206921 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (1206941) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 201151 + ... + 201156.

It is an arithmetic number, because the mean of its divisors is an integer number (402308).

2^1206921 is an apocalyptic number.

It is an amenable number.

1206921 is a deficient number, since it is larger than the sum of its proper divisors (402311).

1206921 is an equidigital number, since it uses as much as digits as its factorization.

1206921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 402310.

The product of its (nonzero) digits is 216, while the sum is 21.

The square root of 1206921 is about 1098.5995630802. The cubic root of 1206921 is about 106.4697615226.

It can be divided in two parts, 12069 and 21, that added together give a triangular number (12090 = T₁₅₅).

The spelling of 1206921 in words is "one million, two hundred six thousand, nine hundred twenty-one".