6661063621 has 16 divisors (see below), whose sum is σ = 6931267200. Its totient is φ = 6393688000.

The previous prime is 6661063561. The next prime is 6661063627. The reversal of 6661063621 is 1263601666.

It is a de Polignac number, because none of the positive numbers 2^k-6661063621 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 (6661063627) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4589946 + ... + 4591396.

It is an arithmetic number, because the mean of its divisors is an integer number (433204200).

Almost surely, 2^6661063621 is an apocalyptic number.

It is an amenable number.

6661063621 is a deficient number, since it is larger than the sum of its proper divisors (270203579).

6661063621 is a wasteful number, since it uses less digits than its factorization.

6661063621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2300.

The product of its (nonzero) digits is 46656, while the sum is 37.

The square root of 6661063621 is about 81615.3393731840. The cubic root of 6661063621 is about 1881.5446431937.

The spelling of 6661063621 in words is "six billion, six hundred sixty-one million, sixty-three thousand, six hundred twenty-one".