1221203420 has 24 divisors (see below), whose sum is σ = 2568709584. Its totient is φ = 487684736.

The previous prime is 1221203419. The next prime is 1221203441. The reversal of 1221203420 is 243021221.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 37142 + ... + 61821.

It is an arithmetic number, because the mean of its divisors is an integer number (107029566).

Almost surely, 2^1221203420 is an apocalyptic number.

1221203420 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221203420 is an abundant number, since it is smaller than the sum of its proper divisors (1347506164).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1221203420 is a wasteful number, since it uses less digits than its factorization.

1221203420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 99589 (or 99587 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 17.

The square root of 1221203420 is about 34945.7210542292. The cubic root of 1221203420 is about 1068.8809507703.

Adding to 1221203420 its reverse (243021221), we get a palindrome (1464224641).

The spelling of 1221203420 in words is "one billion, two hundred twenty-one million, two hundred three thousand, four hundred twenty".