20621845764 has 54 divisors (see below), whose sum is σ = 56445709866. Its totient is φ = 6345181440.

The previous prime is 20621845711. The next prime is 20621845813. The reversal of 20621845764 is 46754812602.

20621845764 is a `hidden beast` number, since 2 + 0 + 62 + 18 + 4 + 576 + 4 = 666.

It can be written as a sum of positive squares in 3 ways, for example, as 729000000 + 19892845764 = 27000^2 + 141042^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 1688677 + ... + 1700844.

Almost surely, 2^20621845764 is an apocalyptic number.

It is an amenable number.

20621845764 is an abundant number, since it is smaller than the sum of its proper divisors (35823864102).

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

20621845764 is a wasteful number, since it uses less digits than its factorization.

20621845764 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3389557 (or 3389539 counting only the distinct ones).

The product of its (nonzero) digits is 645120, while the sum is 45.

The spelling of 20621845764 in words is "twenty billion, six hundred twenty-one million, eight hundred forty-five thousand, seven hundred sixty-four".