1221132520 has 64 divisors (see below), whose sum is σ = 2848789440. Its totient is φ = 470745600.

The previous prime is 1221132509. The next prime is 1221132529. The reversal of 1221132520 is 252311221.

It is not an unprimeable number, because it can be changed into a prime (1221132529) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 131635 + ... + 140605.

It is an arithmetic number, because the mean of its divisors is an integer number (44512335).

Almost surely, 2^1221132520 is an apocalyptic number.

1221132520 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 1221132520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1424394720).

1221132520 is an abundant number, since it is smaller than the sum of its proper divisors (1627656920).

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

1221132520 is a wasteful number, since it uses less digits than its factorization.

1221132520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9106 (or 9102 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 19.

The square root of 1221132520 is about 34944.7066091561. The cubic root of 1221132520 is about 1068.8602648565.

Adding to 1221132520 its reverse (252311221), we get a palindrome (1473443741).

The spelling of 1221132520 in words is "one billion, two hundred twenty-one million, one hundred thirty-two thousand, five hundred twenty".