20721187485 has 96 divisors (see below), whose sum is σ = 40042229760. Its totient is φ = 9864353664.

The previous prime is 20721187469. The next prime is 20721187499. The reversal of 20721187485 is 58478112702.

20721187485 is a `hidden beast` number, since 20 + 72 + 1 + 1 + 87 + 485 = 666.

It is not a de Polignac number, because 20721187485 - 2⁴ = 20721187469 is a prime.

It is a super-3 number, since 3×20721187485³ (a number of 32 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

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

It is a self number, because there is not a number n which added to its sum of digits gives 20721187485.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 1309692 + ... + 1325418.

It is an arithmetic number, because the mean of its divisors is an integer number (417106560).

Almost surely, 2^20721187485 is an apocalyptic number.

It is an amenable number.

20721187485 is a deficient number, since it is larger than the sum of its proper divisors (19321042275).

20721187485 is a wasteful number, since it uses less digits than its factorization.

20721187485 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15847 (or 15844 counting only the distinct ones).

The product of its (nonzero) digits is 250880, while the sum is 45.

The spelling of 20721187485 in words is "twenty billion, seven hundred twenty-one million, one hundred eighty-seven thousand, four hundred eighty-five".