1221015072 has 96 divisors (see below), whose sum is σ = 3510864000. Its totient is φ = 369840128.

The previous prime is 1221015017. The next prime is 1221015077. The reversal of 1221015072 is 2705101221.

It is a tau number, because it is divible by the number of its divisors (96).

It is not an unprimeable number, because it can be changed into a prime (1221015077) 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, 34429 + ... + 60227.

It is an arithmetic number, because the mean of its divisors is an integer number (36571500).

Almost surely, 2^1221015072 is an apocalyptic number.

1221015072 is a gapful number since it is divisible by the number (12) 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 1221015072, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1755432000).

1221015072 is an abundant number, since it is smaller than the sum of its proper divisors (2289848928).

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

1221015072 is a wasteful number, since it uses less digits than its factorization.

1221015072 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25858 (or 25850 counting only the distinct ones).

The product of its (nonzero) digits is 280, while the sum is 21.

The square root of 1221015072 is about 34943.0260853292. The cubic root of 1221015072 is about 1068.8259962512.

Adding to 1221015072 its reverse (2705101221), we get a palindrome (3926116293).

The spelling of 1221015072 in words is "one billion, two hundred twenty-one million, fifteen thousand, seventy-two".