6640015440 has 40 divisors (see below), whose sum is σ = 20584048608. Its totient is φ = 1770670720.

The previous prime is 6640015411. The next prime is 6640015451. The reversal of 6640015440 is 445100466.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 6640015398 and 6640015407.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13833126 + ... + 13833605.

Almost surely, 2^6640015440 is an apocalyptic number.

6640015440 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

6640015440 is an abundant number, since it is smaller than the sum of its proper divisors (13944033168).

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

6640015440 is a wasteful number, since it uses less digits than its factorization.

6640015440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27666747 (or 27666741 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 30.

The square root of 6640015440 is about 81486.2898897723. The cubic root of 6640015440 is about 1879.5607318366.

The spelling of 6640015440 in words is "six billion, six hundred forty million, fifteen thousand, four hundred forty".