13991861520 has 360 divisors, whose sum is σ = 58154331456. Its totient is φ = 2951949312.

The previous prime is 13991861473. The next prime is 13991861557. The reversal of 13991861520 is 2516819931.

13991861520 is a `hidden beast` number, since 1 + 3 + 9 + 9 + 1 + 8 + 615 + 20 = 666.

13991861520 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (360).

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 843547 + ... + 859973.

Almost surely, 2^13991861520 is an apocalyptic number.

13991861520 is a gapful number since it is divisible by the number (10) 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 13991861520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29077165728).

13991861520 is an abundant number, since it is smaller than the sum of its proper divisors (44162469936).

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

13991861520 is a wasteful number, since it uses less digits than its factorization.

13991861520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16479 (or 16457 counting only the distinct ones).

The product of its (nonzero) digits is 116640, while the sum is 45.

The spelling of 13991861520 in words is "thirteen billion, nine hundred ninety-one million, eight hundred sixty-one thousand, five hundred twenty".