20664611540 has 12 divisors (see below), whose sum is σ = 43395684276. Its totient is φ = 8265844608.

The previous prime is 20664611521. The next prime is 20664611567. The reversal of 20664611540 is 4511646602.

It can be written as a sum of positive squares in 2 ways, for example, as 9017021764 + 11647589776 = 94958^2 + 107924^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 20664611540.

It is a congruent number.

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, 516615269 + ... + 516615308.

It is an arithmetic number, because the mean of its divisors is an integer number (3616307023).

Almost surely, 2^20664611540 is an apocalyptic number.

20664611540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20664611540 is an abundant number, since it is smaller than the sum of its proper divisors (22731072736).

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

20664611540 is a wasteful number, since it uses less digits than its factorization.

20664611540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1033230586 (or 1033230584 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 35.

The spelling of 20664611540 in words is "twenty billion, six hundred sixty-four million, six hundred eleven thousand, five hundred forty".