21534151511540 has 24 divisors (see below), whose sum is σ = 45227063254632. Its totient is φ = 8612642494080.

The previous prime is 21534151511539. The next prime is 21534151511603. The reversal of 21534151511540 is 4511515143512.

It can be written as a sum of positive squares in 4 ways, for example, as 5380006026256 + 16154145485284 = 2319484^2 + 4019222^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21534151511494 and 21534151511503.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 63458459 + ... + 63796898.

It is an arithmetic number, because the mean of its divisors is an integer number (1884460968943).

Almost surely, 2^{21534151511540} is an apocalyptic number.

21534151511540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21534151511540 is an abundant number, since it is smaller than the sum of its proper divisors (23692911743092).

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

21534151511540 is a wasteful number, since it uses less digits than its factorization.

21534151511540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 127263827 (or 127263825 counting only the distinct ones).

The product of its (nonzero) digits is 60000, while the sum is 38.

The spelling of 21534151511540 in words is "twenty-one trillion, five hundred thirty-four billion, one hundred fifty-one million, five hundred eleven thousand, five hundred forty".