1217212020 has 72 divisors (see below), whose sum is σ = 3704404704. Its totient is φ = 323517888.

The previous prime is 1217211997. The next prime is 1217212021. The reversal of 1217212020 is 202127121.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 1217211984 and 1217212002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1217212021) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 44247 + ... + 66273.

Almost surely, 2^1217212020 is an apocalyptic number.

1217212020 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 1217212020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1852202352).

1217212020 is an abundant number, since it is smaller than the sum of its proper divisors (2487192684).

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

1217212020 is a wasteful number, since it uses less digits than its factorization.

1217212020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22349 (or 22344 counting only the distinct ones).

The product of its (nonzero) digits is 112, while the sum is 18.

The square root of 1217212020 is about 34888.5657486805. The cubic root of 1217212020 is about 1067.7151641201.

Adding to 1217212020 its reverse (202127121), we get a palindrome (1419339141).

The spelling of 1217212020 in words is "one billion, two hundred seventeen million, two hundred twelve thousand, twenty".