20604020661 has 24 divisors (see below), whose sum is σ = 34049695680. Its totient is φ = 11761019136.

The previous prime is 20604020639. The next prime is 20604020669. The reversal of 20604020661 is 16602040602.

It is a happy number.

It is not a de Polignac number, because 20604020661 - 2¹³ = 20604012469 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20604020669) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 117495 + ... + 234548.

It is an arithmetic number, because the mean of its divisors is an integer number (1418737320).

Almost surely, 2^20604020661 is an apocalyptic number.

20604020661 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

20604020661 is a deficient number, since it is larger than the sum of its proper divisors (13445675019).

20604020661 is a wasteful number, since it uses less digits than its factorization.

20604020661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 352985 (or 352982 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 27.

The spelling of 20604020661 in words is "twenty billion, six hundred four million, twenty thousand, six hundred sixty-one".