20621555528 has 36 divisors (see below), whose sum is σ = 44984339865. Its totient is φ = 8836591008.

The previous prime is 20621555527. The next prime is 20621555561. The reversal of 20621555528 is 82555512602.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

It can be written as a sum of positive squares in 2 ways, for example, as 19470853444 + 1150702084 = 139538^2 + 33922^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=101542.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20621555527) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 2839550 + ... + 2846802.

Almost surely, 2^20621555528 is an apocalyptic number.

20621555528 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

20621555528 is an abundant number, since it is smaller than the sum of its proper divisors (24362784337).

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

20621555528 is an frugal number, since it uses more digits than its factorization.

20621555528 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14526 (or 7262 counting only the distinct ones).

The product of its (nonzero) digits is 240000, while the sum is 41.

The spelling of 20621555528 in words is "twenty billion, six hundred twenty-one million, five hundred fifty-five thousand, five hundred twenty-eight".