20505429888 has 64 divisors (see below), whose sum is σ = 57334281600. Its totient is φ = 6475396608.

The previous prime is 20505429887. The next prime is 20505429949. The reversal of 20505429888 is 88892450502.

It is a tau number, because it is divible by the number of its divisors (64).

It is a self number, because there is not a number n which added to its sum of digits gives 20505429888.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20505429887) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1397956 + ... + 1412547.

It is an arithmetic number, because the mean of its divisors is an integer number (895848150).

Almost surely, 2^20505429888 is an apocalyptic number.

It is an amenable number.

20505429888 is an abundant number, since it is smaller than the sum of its proper divisors (36828851712).

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

20505429888 is a wasteful number, since it uses less digits than its factorization.

20505429888 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2810539 (or 2810527 counting only the distinct ones).

The product of its (nonzero) digits is 1843200, while the sum is 51.

The spelling of 20505429888 in words is "twenty billion, five hundred five million, four hundred twenty-nine thousand, eight hundred eighty-eight".