6661209810 has 128 divisors (see below), whose sum is σ = 17484595200. Its totient is φ = 1617719040.

The previous prime is 6661209787. The next prime is 6661209833. The reversal of 6661209810 is 189021666.

It is an interprime number because it is at equal distance from previous prime (6661209787) and next prime (6661209833).

It is a super-2 number, since 2×6661209810² = 88743432265680472200, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 4478887 + ... + 4480373.

It is an arithmetic number, because the mean of its divisors is an integer number (136598400).

Almost surely, 2^6661209810 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6661209810, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (8742297600).

6661209810 is an abundant number, since it is smaller than the sum of its proper divisors (10823385390).

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

6661209810 is a wasteful number, since it uses less digits than its factorization.

6661209810 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1816.

The product of its (nonzero) digits is 31104, while the sum is 39.

The square root of 6661209810 is about 81616.2349658449. The cubic root of 6661209810 is about 1881.5584077180.

The spelling of 6661209810 in words is "six billion, six hundred sixty-one million, two hundred nine thousand, eight hundred ten".