3215555640 has 144 divisors (see below), whose sum is σ = 11487130200. Its totient is φ = 779518080.

The previous prime is 3215555597. The next prime is 3215555653. The reversal of 3215555640 is 465555123.

3215555640 is a `hidden beast` number, since 3 + 2 + 1 + 5 + 5 + 5 + 5 + 640 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 3215555595 and 3215555604.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 6651 + ... + 80469.

Almost surely, 2^3215555640 is an apocalyptic number.

3215555640 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 3215555640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (5743565100).

3215555640 is an abundant number, since it is smaller than the sum of its proper divisors (8271574560).

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

3215555640 is a wasteful number, since it uses less digits than its factorization.

3215555640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73858 (or 73840 counting only the distinct ones).

The product of its (nonzero) digits is 90000, while the sum is 36.

The square root of 3215555640 is about 56705.8695374650. The cubic root of 3215555640 is about 1475.9965518680.

It can be divided in two parts, 3215 and 555640, that added together give a palindrome (558855).

The spelling of 3215555640 in words is "three billion, two hundred fifteen million, five hundred fifty-five thousand, six hundred forty".