1500165661 has 4 divisors (see below), whose sum is σ = 1501152192. Its totient is φ = 1499179132.

The previous prime is 1500165659. The next prime is 1500165673. The reversal of 1500165661 is 1665610051.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1665610051 = 7 ⋅237944293.

It is a cyclic number.

It is not a de Polignac number, because 1500165661 - 2¹ = 1500165659 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1500160661) 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 3 ways as a sum of consecutive naturals, for example, 490981 + ... + 494026.

It is an arithmetic number, because the mean of its divisors is an integer number (375288048).

Almost surely, 2^1500165661 is an apocalyptic number.

It is an amenable number.

1500165661 is a deficient number, since it is larger than the sum of its proper divisors (986531).

1500165661 is an equidigital number, since it uses as much as digits as its factorization.

1500165661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 986530.

The product of its (nonzero) digits is 5400, while the sum is 31.

The square root of 1500165661 is about 38731.9720773420. The cubic root of 1500165661 is about 1144.7563820034.

The spelling of 1500165661 in words is "one billion, five hundred million, one hundred sixty-five thousand, six hundred sixty-one".