1661511615 has 32 divisors (see below), whose sum is σ = 2723635200. Its totient is φ = 864452736.

The previous prime is 1661511613. The next prime is 1661511629. The reversal of 1661511615 is 5161151661.

It is not a de Polignac number, because 1661511615 - 2¹ = 1661511613 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661511613) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 998274 + ... + 999936.

It is an arithmetic number, because the mean of its divisors is an integer number (85113600).

Almost surely, 2^1661511615 is an apocalyptic number.

1661511615 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1661511615 is a deficient number, since it is larger than the sum of its proper divisors (1062123585).

1661511615 is a wasteful number, since it uses less digits than its factorization.

1661511615 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3263.

The product of its digits is 5400, while the sum is 33.

The square root of 1661511615 is about 40761.6439192533. The cubic root of 1661511615 is about 1184.4074411045.

The spelling of 1661511615 in words is "one billion, six hundred sixty-one million, five hundred eleven thousand, six hundred fifteen".