15990438537540 has 144 divisors (see below), whose sum is σ = 51364099043712. Its totient is φ = 4012772901888.

The previous prime is 15990438537533. The next prime is 15990438537617. The reversal of 15990438537540 is 4573583409951.

15990438537540 is a `hidden beast` number, since 1 + 5 + 9 + 9 + 0 + 4 + 3 + 85 + 3 + 7 + 540 = 666.

It is a super-4 number, since 4×15990438537540⁴ (a number of 54 digits) contains 4444 as substring.

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 47 ways as a sum of consecutive naturals, for example, 23864977 + ... + 24525863.

It is an arithmetic number, because the mean of its divisors is an integer number (356695132248).

Almost surely, 2^{15990438537540} is an apocalyptic number.

15990438537540 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 15990438537540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25682049521856).

15990438537540 is an abundant number, since it is smaller than the sum of its proper divisors (35373660506172).

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

15990438537540 is a wasteful number, since it uses less digits than its factorization.

15990438537540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 668826 (or 668821 counting only the distinct ones).

The product of its (nonzero) digits is 81648000, while the sum is 63.

The spelling of 15990438537540 in words is "fifteen trillion, nine hundred ninety billion, four hundred thirty-eight million, five hundred thirty-seven thousand, five hundred forty".