1221201000 has 192 divisors, whose sum is σ = 4216942080. Its totient is φ = 318614400.

The previous prime is 1221200993. The next prime is 1221201019. The reversal of 1221201000 is 1021221.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 421557 + ... + 424443.

It is an arithmetic number, because the mean of its divisors is an integer number (21963240).

Almost surely, 2^1221201000 is an apocalyptic number.

1221201000 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 1221201000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2108471040).

1221201000 is an abundant number, since it is smaller than the sum of its proper divisors (2995741080).

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

1221201000 is a wasteful number, since it uses less digits than its factorization.

1221201000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2961 (or 2944 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

The square root of 1221201000 is about 34945.6864290859. The cubic root of 1221201000 is about 1068.8802447199.

Adding to 1221201000 its reverse (1021221), we get a palindrome (1222222221).

The spelling of 1221201000 in words is "one billion, two hundred twenty-one million, two hundred one thousand".