1266421821 has 16 divisors (see below), whose sum is σ = 1931395200. Its totient is φ = 723066048.

The previous prime is 1266421813. The next prime is 1266421823. The reversal of 1266421821 is 1281246621.

It is a happy number.

It is not a de Polignac number, because 1266421821 - 2³ = 1266421813 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1266421823) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1275 + ... + 50343.

It is an arithmetic number, because the mean of its divisors is an integer number (120712200).

Almost surely, 2^1266421821 is an apocalyptic number.

It is an amenable number.

1266421821 is a deficient number, since it is larger than the sum of its proper divisors (664973379).

1266421821 is a wasteful number, since it uses less digits than its factorization.

1266421821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50308.

The product of its digits is 9216, while the sum is 33.

The square root of 1266421821 is about 35586.8208892000. The cubic root of 1266421821 is about 1081.9141354890.

The spelling of 1266421821 in words is "one billion, two hundred sixty-six million, four hundred twenty-one thousand, eight hundred twenty-one".