1221131220210 has 256 divisors, whose sum is σ = 3653337600000. Its totient is φ = 287688360960.

The previous prime is 1221131220191. The next prime is 1221131220217. The reversal of 1221131220210 is 120221311221.

1221131220210 is a `hidden beast` number, since 1 + 221 + 13 + 1 + 220 + 210 = 666.

It is a super-2 number, since 2×1221131220210² (a number of 25 digits) contains 22 as substring.

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

It is not an unprimeable number, because it can be changed into a prime (1221131220217) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 25390266 + ... + 25438314.

It is an arithmetic number, because the mean of its divisors is an integer number (14270850000).

Almost surely, 2^{1221131220210} is an apocalyptic number.

1221131220210 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 1221131220210, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1826668800000).

1221131220210 is an abundant number, since it is smaller than the sum of its proper divisors (2432206379790).

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

1221131220210 is a wasteful number, since it uses less digits than its factorization.

1221131220210 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48318 (or 48312 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 18.

Adding to 1221131220210 its reverse (120221311221), we get a palindrome (1341352531431).

The spelling of 1221131220210 in words is "one trillion, two hundred twenty-one billion, one hundred thirty-one million, two hundred twenty thousand, two hundred ten".