20661285919 has 6 divisors (see below), whose sum is σ = 21805955880. Its totient is φ = 19573849476.

The previous prime is 20661285913. The next prime is 20661285947. The reversal of 20661285919 is 91958216602.

It is not a de Polignac number, because 20661285919 - 2¹³ = 20661277727 is a prime.

It is a super-2 number, since 2×20661285919² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20661285913) 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 5 ways as a sum of consecutive naturals, for example, 28616379 + ... + 28617100.

It is an arithmetic number, because the mean of its divisors is an integer number (3634325980).

Almost surely, 2^20661285919 is an apocalyptic number.

20661285919 is a deficient number, since it is larger than the sum of its proper divisors (1144669961).

20661285919 is an equidigital number, since it uses as much as digits as its factorization.

20661285919 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57233517 (or 57233498 counting only the distinct ones).

The product of its (nonzero) digits is 466560, while the sum is 49.

The spelling of 20661285919 in words is "twenty billion, six hundred sixty-one million, two hundred eighty-five thousand, nine hundred nineteen".