20690781804 has 384 divisors, whose sum is σ = 74550067200. Its totient is φ = 4791260160.

The previous prime is 20690781779. The next prime is 20690781817. The reversal of 20690781804 is 40818709602.

It is a self number, because there is not a number n which added to its sum of digits gives 20690781804.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 2682217 + ... + 2689919.

It is an arithmetic number, because the mean of its divisors is an integer number (194140800).

Almost surely, 2^20690781804 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20690781804, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37275033600).

20690781804 is an abundant number, since it is smaller than the sum of its proper divisors (53859285396).

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

20690781804 is a wasteful number, since it uses less digits than its factorization.

20690781804 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7770 (or 7762 counting only the distinct ones).

The product of its (nonzero) digits is 193536, while the sum is 45.

The spelling of 20690781804 in words is "twenty billion, six hundred ninety million, seven hundred eighty-one thousand, eight hundred four".