1221310020 has 48 divisors (see below), whose sum is σ = 3908193408. Its totient is φ = 279156480.

The previous prime is 1221310001. The next prime is 1221310033. The reversal of 1221310020 is 200131221.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 1221309978 and 1221310005.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1453521 + ... + 1454360.

It is an arithmetic number, because the mean of its divisors is an integer number (81420696).

Almost surely, 2^1221310020 is an apocalyptic number.

1221310020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221310020 is an abundant number, since it is smaller than the sum of its proper divisors (2686883388).

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

1221310020 is a wasteful number, since it uses less digits than its factorization.

1221310020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2907900 (or 2907898 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 1221310020 is about 34947.2462434453. The cubic root of 1221310020 is about 1068.9120510747.

Adding to 1221310020 its reverse (200131221), we get a palindrome (1421441241).

The spelling of 1221310020 in words is "one billion, two hundred twenty-one million, three hundred ten thousand, twenty".