1661387516 has 12 divisors (see below), whose sum is σ = 2907725688. Its totient is φ = 830608752.

The previous prime is 1661387513. The next prime is 1661387573. The reversal of 1661387516 is 6157831661.

It is a hoax number, since the sum of its digits (44) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661387513) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 47270 + ... + 74546.

It is an arithmetic number, because the mean of its divisors is an integer number (242310474).

Almost surely, 2^1661387516 is an apocalyptic number.

It is an amenable number.

1661387516 is a deficient number, since it is larger than the sum of its proper divisors (1246338172).

1661387516 is a wasteful number, since it uses less digits than its factorization.

1661387516 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42508 (or 42506 counting only the distinct ones).

The product of its digits is 181440, while the sum is 44.

The square root of 1661387516 is about 40760.1216386801. The cubic root of 1661387516 is about 1184.3779524073.

The spelling of 1661387516 in words is "one billion, six hundred sixty-one million, three hundred eighty-seven thousand, five hundred sixteen".