6649251840 has 576 divisors, whose sum is σ = 28762231680. Its totient is φ = 1380188160.

The previous prime is 6649251811. The next prime is 6649251857. The reversal of 6649251840 is 481529466.

6649251840 is a `hidden beast` number, since 6 + 6 + 4 + 92 + 518 + 40 = 666.

It is a tau number, because it is divible by the number of its divisors (576).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 7095852 + ... + 7096788.

It is an arithmetic number, because the mean of its divisors is an integer number (49934430).

Almost surely, 2^6649251840 is an apocalyptic number.

6649251840 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 6649251840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (14381115840).

6649251840 is an abundant number, since it is smaller than the sum of its proper divisors (22112979840).

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

6649251840 is a wasteful number, since it uses less digits than its factorization.

6649251840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 988 (or 965 counting only the distinct ones).

The product of its (nonzero) digits is 414720, while the sum is 45.

The square root of 6649251840 is about 81542.9447591881. The cubic root of 6649251840 is about 1880.4318307855.

The spelling of 6649251840 in words is "six billion, six hundred forty-nine million, two hundred fifty-one thousand, eight hundred forty".