1215000020 has 24 divisors (see below), whose sum is σ = 2747769864. Its totient is φ = 448615296.

The previous prime is 1214999999. The next prime is 1215000023. The reversal of 1215000020 is 200005121.

It can be written as a sum of positive squares in 4 ways, for example, as 8271376 + 1206728644 = 2876^2 + 34738^2 .

It is a junction number, because it is equal to n+sod(n) for n = 1214999965 and 1215000010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1215000023) 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, 2336279 + ... + 2336798.

It is an arithmetic number, because the mean of its divisors is an integer number (114490411).

Almost surely, 2^1215000020 is an apocalyptic number.

1215000020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1215000020 is an abundant number, since it is smaller than the sum of its proper divisors (1532769844).

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

1215000020 is a wasteful number, since it uses less digits than its factorization.

1215000020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4673099 (or 4673097 counting only the distinct ones).

The product of its (nonzero) digits is 20, while the sum is 11.

The square root of 1215000020 is about 34856.8504027544. The cubic root of 1215000020 is about 1067.0679972020.

Adding to 1215000020 its reverse (200005121), we get a palindrome (1415005141).

The spelling of 1215000020 in words is "one billion, two hundred fifteen million, twenty", and thus it is an aban number.