1226218921 has 4 divisors (see below), whose sum is σ = 1227337812. Its totient is φ = 1225100032.

The previous prime is 1226218879. The next prime is 1226218927. The reversal of 1226218921 is 1298126221.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1298126221 = 7 ⋅185446603.

It can be written as a sum of positive squares in 2 ways, for example, as 668739600 + 557479321 = 25860^2 + 23611^2 .

It is a cyclic number.

It is not a de Polignac number, because 1226218921 - 2¹³ = 1226210729 is a prime.

It is a super-2 number, since 2×1226218921² = 3007225684436808482, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1226218927) 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, 557800 + ... + 559993.

It is an arithmetic number, because the mean of its divisors is an integer number (306834453).

Almost surely, 2^1226218921 is an apocalyptic number.

It is an amenable number.

1226218921 is a deficient number, since it is larger than the sum of its proper divisors (1118891).

1226218921 is a wasteful number, since it uses less digits than its factorization.

1226218921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1118890.

The product of its digits is 6912, while the sum is 34.

The square root of 1226218921 is about 35017.4088276103. The cubic root of 1226218921 is about 1070.3422554937.

The spelling of 1226218921 in words is "one billion, two hundred twenty-six million, two hundred eighteen thousand, nine hundred twenty-one".