3661981440 has 288 divisors, whose sum is σ = 12729541440. Its totient is φ = 891813888.

The previous prime is 3661981429. The next prime is 3661981469. The reversal of 3661981440 is 441891663.

It is a junction number, because it is equal to n+sod(n) for n = 3661981392 and 3661981401.

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 31 ways as a sum of consecutive naturals, for example, 5440944 + ... + 5441616.

Almost surely, 2^3661981440 is an apocalyptic number.

3661981440 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 3661981440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (6364770720).

3661981440 is an abundant number, since it is smaller than the sum of its proper divisors (9067560000).

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

3661981440 is a wasteful number, since it uses less digits than its factorization.

3661981440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 819 (or 805 counting only the distinct ones).

The product of its (nonzero) digits is 124416, while the sum is 42.

The square root of 3661981440 is about 60514.3077296601. The cubic root of 3661981440 is about 1541.3645969587.

The spelling of 3661981440 in words is "three billion, six hundred sixty-one million, nine hundred eighty-one thousand, four hundred forty".