2015501661 has 24 divisors (see below), whose sum is σ = 3041301120. Its totient is φ = 1283790816.

The previous prime is 2015501659. The next prime is 2015501687. The reversal of 2015501661 is 1661055102.

It is a happy number.

It is not a de Polignac number, because 2015501661 - 2¹ = 2015501659 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2015501161) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 195135 + ... + 205203.

It is an arithmetic number, because the mean of its divisors is an integer number (126720880).

Almost surely, 2^2015501661 is an apocalyptic number.

It is an amenable number.

2015501661 is a deficient number, since it is larger than the sum of its proper divisors (1025799459).

2015501661 is a wasteful number, since it uses less digits than its factorization.

2015501661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11065 (or 11062 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 27.

The square root of 2015501661 is about 44894.3388524656. The cubic root of 2015501661 is about 1263.1678207309.

Adding to 2015501661 its reverse (1661055102), we get a palindrome (3676556763).

The spelling of 2015501661 in words is "two billion, fifteen million, five hundred one thousand, six hundred sixty-one".