20997532530 has 128 divisors (see below), whose sum is σ = 61703389440. Its totient is φ = 5048386560.

The previous prime is 20997532511. The next prime is 20997532537. The reversal of 20997532530 is 3523579902.

20997532530 is a `hidden beast` number, since 20 + 9 + 97 + 5 + 3 + 2 + 530 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20997532537) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 81370 + ... + 220490.

It is an arithmetic number, because the mean of its divisors is an integer number (482057730).

Almost surely, 2^20997532530 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20997532530, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30851694720).

20997532530 is an abundant number, since it is smaller than the sum of its proper divisors (40705856910).

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

20997532530 is a wasteful number, since it uses less digits than its factorization.

20997532530 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 139193 (or 139187 counting only the distinct ones).

The product of its (nonzero) digits is 510300, while the sum is 45.

The spelling of 20997532530 in words is "twenty billion, nine hundred ninety-seven million, five hundred thirty-two thousand, five hundred thirty".