16661001276 has 72 divisors (see below), whose sum is σ = 44655745680. Its totient is φ = 5222935296.

The previous prime is 16661001271. The next prime is 16661001281. The reversal of 16661001276 is 67210016661.

It is an interprime number because it is at equal distance from previous prime (16661001271) and next prime (16661001281).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 16661001276.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16661001271) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4810 + ... + 182606.

It is an arithmetic number, because the mean of its divisors is an integer number (620218690).

Almost surely, 2^16661001276 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 16661001276, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22327872840).

16661001276 is an abundant number, since it is smaller than the sum of its proper divisors (27994744404).

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

16661001276 is a wasteful number, since it uses less digits than its factorization.

16661001276 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 177963 (or 177958 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 36.

The spelling of 16661001276 in words is "sixteen billion, six hundred sixty-one million, one thousand, two hundred seventy-six".