21541252520 has 16 divisors (see below), whose sum is σ = 48467818260. Its totient is φ = 8616500992.

The previous prime is 21541252511. The next prime is 21541252541. The reversal of 21541252520 is 2525214512.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 17813173156 + 3728079364 = 133466^2 + 61058^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 269265617 + ... + 269265696.

Almost surely, 2^21541252520 is an apocalyptic number.

21541252520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21541252520 is an abundant number, since it is smaller than the sum of its proper divisors (26926565740).

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

21541252520 is a wasteful number, since it uses less digits than its factorization.

21541252520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 538531324 (or 538531320 counting only the distinct ones).

The product of its (nonzero) digits is 8000, while the sum is 29.

The spelling of 21541252520 in words is "twenty-one billion, five hundred forty-one million, two hundred fifty-two thousand, five hundred twenty".