1221055421 has 8 divisors (see below), whose sum is σ = 1233822720. Its totient is φ = 1208305872.

The previous prime is 1221055397. The next prime is 1221055427. The reversal of 1221055421 is 1245501221.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1221055421 - 2²⁶ = 1153946557 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221055427) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 168356 + ... + 175458.

It is an arithmetic number, because the mean of its divisors is an integer number (154227840).

Almost surely, 2^1221055421 is an apocalyptic number.

It is an amenable number.

1221055421 is a deficient number, since it is larger than the sum of its proper divisors (12767299).

1221055421 is a wasteful number, since it uses less digits than its factorization.

1221055421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8875.

The product of its (nonzero) digits is 800, while the sum is 23.

The square root of 1221055421 is about 34943.6034346774. The cubic root of 1221055421 is about 1068.8377694023.

Adding to 1221055421 its reverse (1245501221), we get a palindrome (2466556642).

The spelling of 1221055421 in words is "one billion, two hundred twenty-one million, fifty-five thousand, four hundred twenty-one".