1221132145500 has 240 divisors, whose sum is σ = 4091646022464. Its totient is φ = 316833897600.

The previous prime is 1221132145487. The next prime is 1221132145553. The reversal of 1221132145500 is 55412311221.

It is a happy number.

1221132145500 is a `hidden beast` number, since 1 + 2 + 2 + 1 + 13 + 2 + 145 + 500 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 1091049 + ... + 1905951.

Almost surely, 2^{1221132145500} is an apocalyptic number.

1221132145500 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 1221132145500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2045823011232).

1221132145500 is an abundant number, since it is smaller than the sum of its proper divisors (2870513876964).

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

1221132145500 is a wasteful number, since it uses less digits than its factorization.

1221132145500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 814971 (or 814950 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 27.

Adding to 1221132145500 its reverse (55412311221), we get a palindrome (1276544456721).

The spelling of 1221132145500 in words is "one trillion, two hundred twenty-one billion, one hundred thirty-two million, one hundred forty-five thousand, five hundred".