21511522334540 has 96 divisors (see below), whose sum is σ = 51678257178240. Its totient is φ = 7368153513984.

The previous prime is 21511522334531. The next prime is 21511522334557. The reversal of 21511522334540 is 4543322511512.

It is a junction number, because it is equal to n+sod(n) for n = 21511522334494 and 21511522334503.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 672030056 + ... + 672062064.

It is an arithmetic number, because the mean of its divisors is an integer number (538315178940).

Almost surely, 2^{21511522334540} is an apocalyptic number.

21511522334540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21511522334540 is an abundant number, since it is smaller than the sum of its proper divisors (30166734843700).

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

21511522334540 is a wasteful number, since it uses less digits than its factorization.

21511522334540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36579 (or 36577 counting only the distinct ones).

The product of its (nonzero) digits is 144000, while the sum is 38.

The spelling of 21511522334540 in words is "twenty-one trillion, five hundred eleven billion, five hundred twenty-two million, three hundred thirty-four thousand, five hundred forty".