1213221020 has 144 divisors (see below), whose sum is σ = 2973003264. Its totient is φ = 414691200.

The previous prime is 1213221017. The next prime is 1213221029. The reversal of 1213221020 is 201223121.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 1213220986 and 1213221004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1213221029) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3951707 + ... + 3952013.

It is an arithmetic number, because the mean of its divisors is an integer number (20645856).

Almost surely, 2^1213221020 is an apocalyptic number.

1213221020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1213221020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1486501632).

1213221020 is an abundant number, since it is smaller than the sum of its proper divisors (1759782244).

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

1213221020 is a wasteful number, since it uses less digits than its factorization.

1213221020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 432 (or 419 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 14.

The square root of 1213221020 is about 34831.3223980945. The cubic root of 1213221020 is about 1066.5469433769.

Adding to 1213221020 its reverse (201223121), we get a palindrome (1414444141).

The spelling of 1213221020 in words is "one billion, two hundred thirteen million, two hundred twenty-one thousand, twenty".