2015121690 has 96 divisors (see below), whose sum is σ = 5583511440. Its totient is φ = 502474752.

The previous prime is 2015121671. The next prime is 2015121721. The reversal of 2015121690 is 961215102.

It can be written as a sum of positive squares in 8 ways, for example, as 1355196969 + 659924721 = 36813^2 + 25689^2 .

It is a super-2 number, since 2×2015121690² = 8121430851016912200, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 236016 + ... + 244404.

Almost surely, 2^2015121690 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2015121690, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2791755720).

2015121690 is an abundant number, since it is smaller than the sum of its proper divisors (3568389750).

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

2015121690 is a wasteful number, since it uses less digits than its factorization.

2015121690 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8576 (or 8573 counting only the distinct ones).

The product of its (nonzero) digits is 1080, while the sum is 27.

The square root of 2015121690 is about 44890.1068165359. The cubic root of 2015121690 is about 1263.0884364740.

Adding to 2015121690 its reverse (961215102), we get a palindrome (2976336792).

The spelling of 2015121690 in words is "two billion, fifteen million, one hundred twenty-one thousand, six hundred ninety".