6645227640 has 128 divisors (see below), whose sum is σ = 20115501120. Its totient is φ = 1756160000.

The previous prime is 6645227623. The next prime is 6645227647. The reversal of 6645227640 is 467225466.

It is a junction number, because it is equal to n+sod(n) for n = 6645227592 and 6645227601.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6645227647) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 9479290 + ... + 9479990.

Almost surely, 2^6645227640 is an apocalyptic number.

6645227640 is a gapful number since it is divisible by the number (60) 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 6645227640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (10057750560).

6645227640 is an abundant number, since it is smaller than the sum of its proper divisors (13470273480).

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

6645227640 is a wasteful number, since it uses less digits than its factorization.

6645227640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1313 (or 1309 counting only the distinct ones).

The product of its (nonzero) digits is 483840, while the sum is 42.

The square root of 6645227640 is about 81518.2656832197. The cubic root of 6645227640 is about 1880.0524015875.

The spelling of 6645227640 in words is "six billion, six hundred forty-five million, two hundred twenty-seven thousand, six hundred forty".