1267821 has 6 divisors (see below), whose sum is σ = 1831310. Its totient is φ = 845208.

The previous prime is 1267789. The next prime is 1267823. The reversal of 1267821 is 1287621.

It can be written as a sum of positive squares in only one way, i.e., 1232100 + 35721 = 1110^2 + 189^2 .

It is not a de Polignac number, because 1267821 - 2⁵ = 1267789 is a prime.

It is a Duffinian number.

1267821 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1267823) 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 5 ways as a sum of consecutive naturals, for example, 70426 + ... + 70443.

2^1267821 is an apocalyptic number.

It is an amenable number.

1267821 is a deficient number, since it is larger than the sum of its proper divisors (563489).

1267821 is a wasteful number, since it uses less digits than its factorization.

1267821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 140875 (or 140872 counting only the distinct ones).

The product of its digits is 1344, while the sum is 27.

The square root of 1267821 is about 1125.9755769998. The cubic root of 1267821 is about 108.2312432055.

The spelling of 1267821 in words is "one million, two hundred sixty-seven thousand, eight hundred twenty-one".