1213545220 has 48 divisors (see below), whose sum is σ = 2637024768. Its totient is φ = 468622080.

The previous prime is 1213545197. The next prime is 1213545227. The reversal of 1213545220 is 225453121.

It is not an unprimeable number, because it can be changed into a prime (1213545227) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 281199 + ... + 285481.

It is an arithmetic number, because the mean of its divisors is an integer number (54938016).

Almost surely, 2^1213545220 is an apocalyptic number.

1213545220 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 1213545220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1318512384).

1213545220 is an abundant number, since it is smaller than the sum of its proper divisors (1423479548).

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

1213545220 is a wasteful number, since it uses less digits than its factorization.

1213545220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4780 (or 4778 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 25.

The square root of 1213545220 is about 34835.9759444170. The cubic root of 1213545220 is about 1066.6419367096.

Adding to 1213545220 its reverse (225453121), we get a palindrome (1438998341).

The spelling of 1213545220 in words is "one billion, two hundred thirteen million, five hundred forty-five thousand, two hundred twenty".