1221612531000 has 256 divisors, whose sum is σ = 3840302568960. Its totient is φ = 323305113600.

The previous prime is 1221612530987. The next prime is 1221612531001. The reversal of 1221612531000 is 1352161221.

It is a happy number.

It is a super-2 number, since 2×1221612531000² (a number of 25 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221612531001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 229494339 + ... + 229499661.

It is an arithmetic number, because the mean of its divisors is an integer number (15001181910).

Almost surely, 2^{1221612531000} is an apocalyptic number.

1221612531000 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 1221612531000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1920151284480).

1221612531000 is an abundant number, since it is smaller than the sum of its proper divisors (2618690037960).

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

1221612531000 is a wasteful number, since it uses less digits than its factorization.

1221612531000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5911 (or 5897 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 24.

Adding to 1221612531000 its reverse (1352161221), we get a palindrome (1222964692221).

The spelling of 1221612531000 in words is "one trillion, two hundred twenty-one billion, six hundred twelve million, five hundred thirty-one thousand".