3947408640 has 864 divisors, whose sum is σ = 16963564800. Its totient is φ = 877879296.

The previous prime is 3947408627. The next prime is 3947408657. The reversal of 3947408640 is 468047493.

It is a tau number, because it is divible by the number of its divisors (864).

It is a super-2 number, since 2×3947408640² = 31164069942293299200, which contains 22 as substring.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 106686702 + ... + 106686738.

Almost surely, 2^3947408640 is an apocalyptic number.

3947408640 is a gapful number since it is divisible by the number (30) 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 3947408640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (8481782400).

3947408640 is an abundant number, since it is smaller than the sum of its proper divisors (13016156160).

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

3947408640 is an frugal number, since it uses more digits than its factorization.

3947408640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 94 (or 54 counting only the distinct ones).

The product of its (nonzero) digits is 580608, while the sum is 45.

The square root of 3947408640 is about 62828.4063143416. The cubic root of 3947408640 is about 1580.4133725862.

The spelling of 3947408640 in words is "three billion, nine hundred forty-seven million, four hundred eight thousand, six hundred forty".