1221013120 has 64 divisors (see below), whose sum is σ = 3013194240. Its totient is φ = 472642560.

The previous prime is 1221013109. The next prime is 1221013127. The reversal of 1221013120 is 213101221.

It is a tau number, because it is divible by the number of its divisors (64).

It is a self number, because there is not a number n which added to its sum of digits gives 1221013120.

It is not an unprimeable number, because it can be changed into a prime (1221013127) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10932 + ... + 50611.

It is an arithmetic number, because the mean of its divisors is an integer number (47081160).

Almost surely, 2^1221013120 is an apocalyptic number.

1221013120 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221013120 is an abundant number, since it is smaller than the sum of its proper divisors (1792181120).

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

1221013120 is an equidigital number, since it uses as much as digits as its factorization.

1221013120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 61593 (or 61581 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 13.

The square root of 1221013120 is about 34942.9981541367. The cubic root of 1221013120 is about 1068.8254266842.

Adding to 1221013120 its reverse (213101221), we get a palindrome (1434114341).

The spelling of 1221013120 in words is "one billion, two hundred twenty-one million, thirteen thousand, one hundred twenty".