1666501616 has 80 divisors (see below), whose sum is σ = 3665390400. Its totient is φ = 728217600.

The previous prime is 1666501591. The next prime is 1666501637. The reversal of 1666501616 is 6161056661.

It is a happy number.

It is a super-2 number, since 2×1666501616² = 5554455272261222912, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1666501616.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 481460 + ... + 484908.

It is an arithmetic number, because the mean of its divisors is an integer number (45817380).

Almost surely, 2^1666501616 is an apocalyptic number.

1666501616 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1666501616, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1832695200).

1666501616 is an abundant number, since it is smaller than the sum of its proper divisors (1998888784).

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

1666501616 is a wasteful number, since it uses less digits than its factorization.

1666501616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3594 (or 3588 counting only the distinct ones).

The product of its (nonzero) digits is 38880, while the sum is 38.

The square root of 1666501616 is about 40822.8075467624. The cubic root of 1666501616 is about 1185.5919623639.

The spelling of 1666501616 in words is "one billion, six hundred sixty-six million, five hundred one thousand, six hundred sixteen".