1215720000 has 420 divisors, whose sum is σ = 4765736976. Its totient is φ = 293760000.

The previous prime is 1215719977. The next prime is 1215720013. The reversal of 1215720000 is 275121.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 3959847 + ... + 3960153.

Almost surely, 2^1215720000 is an apocalyptic number.

1215720000 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 1215720000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2382868488).

1215720000 is an abundant number, since it is smaller than the sum of its proper divisors (3550016976).

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

1215720000 is a wasteful number, since it uses less digits than its factorization.

1215720000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 356 (or 328 counting only the distinct ones).

The product of its (nonzero) digits is 140, while the sum is 18.

The square root of 1215720000 is about 34867.1765418423. The cubic root of 1215720000 is about 1067.2787285879.

Adding to 1215720000 its reverse (275121), we get a palindrome (1215995121).

The spelling of 1215720000 in words is "one billion, two hundred fifteen million, seven hundred twenty thousand".