3656981520 has 400 divisors, whose sum is σ = 13635935280. Its totient is φ = 905084928.

The previous prime is 3656981507. The next prime is 3656981527. The reversal of 3656981520 is 251896563.

3656981520 is a `hidden beast` number, since 3 + 6 + 569 + 81 + 5 + 2 + 0 = 666.

It can be written as a sum of positive squares in 8 ways, for example, as 16548624 + 3640432896 = 4068^2 + 60336^2 .

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3656981527) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 9804054 + ... + 9804426.

Almost surely, 2^3656981520 is an apocalyptic number.

3656981520 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 3656981520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (6817967640).

3656981520 is an abundant number, since it is smaller than the sum of its proper divisors (9978953760).

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

3656981520 is a wasteful number, since it uses less digits than its factorization.

3656981520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 504 (or 489 counting only the distinct ones).

The product of its (nonzero) digits is 388800, while the sum is 45.

The square root of 3656981520 is about 60472.9817356479. The cubic root of 3656981520 is about 1540.6627720100.

The spelling of 3656981520 in words is "three billion, six hundred fifty-six million, nine hundred eighty-one thousand, five hundred twenty".