6739721640 has 288 divisors, whose sum is σ = 23173193160. Its totient is φ = 1763596800.

The previous prime is 6739721623. The next prime is 6739721657. The reversal of 6739721640 is 461279376.

6739721640 is a `hidden beast` number, since 6 + 7 + 397 + 216 + 40 = 666.

It is an interprime number because it is at equal distance from previous prime (6739721623) and next prime (6739721657).

It can be written as a sum of positive squares in 4 ways, for example, as 1258688484 + 5481033156 = 35478^2 + 74034^2 .

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 71 ways as a sum of consecutive naturals, for example, 16008630 + ... + 16009050.

Almost surely, 2^6739721640 is an apocalyptic number.

6739721640 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 6739721640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (11586596580).

6739721640 is an abundant number, since it is smaller than the sum of its proper divisors (16433471520).

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

6739721640 is an equidigital number, since it uses as much as digits as its factorization.

6739721640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 517 (or 492 counting only the distinct ones).

The product of its (nonzero) digits is 381024, while the sum is 45.

The square root of 6739721640 is about 82095.8076883345. The cubic root of 6739721640 is about 1888.9218340480.

The spelling of 6739721640 in words is "six billion, seven hundred thirty-nine million, seven hundred twenty-one thousand, six hundred forty".