21286531643540 has 48 divisors (see below), whose sum is σ = 45558332246784. Its totient is φ = 8352208425600.

The previous prime is 21286531643353. The next prime is 21286531643549. The reversal of 21286531643540 is 4534613568212.

It is a super-2 number, since 2×21286531643540² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21286531643549) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 23323346 + ... + 24218825.

It is an arithmetic number, because the mean of its divisors is an integer number (949131921808).

Almost surely, 2^{21286531643540} is an apocalyptic number.

21286531643540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21286531643540 is an abundant number, since it is smaller than the sum of its proper divisors (24271800603244).

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

21286531643540 is a wasteful number, since it uses less digits than its factorization.

21286531643540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47542608 (or 47542606 counting only the distinct ones).

The product of its (nonzero) digits is 4147200, while the sum is 50.

The spelling of 21286531643540 in words is "twenty-one trillion, two hundred eighty-six billion, five hundred thirty-one million, six hundred forty-three thousand, five hundred forty".