16661501 has 4 divisors (see below), whose sum is σ = 16673532. Its totient is φ = 16649472.

The previous prime is 16661483. The next prime is 16661509. The reversal of 16661501 is 10516661.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 6895876 + 9765625 = 2626^2 + 3125^2 .

It is a cyclic number.

It is not a de Polignac number, because 16661501 - 2²² = 12467197 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 (16661509) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3620 + ... + 6813.

It is an arithmetic number, because the mean of its divisors is an integer number (4168383).

Almost surely, 2^16661501 is an apocalyptic number.

It is an amenable number.

16661501 is a deficient number, since it is larger than the sum of its proper divisors (12031).

16661501 is a wasteful number, since it uses less digits than its factorization.

16661501 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12030.

The product of its (nonzero) digits is 1080, while the sum is 26.

The square root of 16661501 is about 4081.8501932335. The cubic root of 16661501 is about 255.4100847437.

The spelling of 16661501 in words is "sixteen million, six hundred sixty-one thousand, five hundred one".