20621785920 has 112 divisors (see below), whose sum is σ = 65536194048. Its totient is φ = 5493934080.

The previous prime is 20621785913. The next prime is 20621785957. The reversal of 20621785920 is 2958712602.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 1062705 + ... + 1081935.

Almost surely, 2^20621785920 is an apocalyptic number.

20621785920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20621785920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32768097024).

20621785920 is an abundant number, since it is smaller than the sum of its proper divisors (44914408128).

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

20621785920 is a wasteful number, since it uses less digits than its factorization.

20621785920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20368 (or 20358 counting only the distinct ones).

The product of its (nonzero) digits is 120960, while the sum is 42.

The spelling of 20621785920 in words is "twenty billion, six hundred twenty-one million, seven hundred eighty-five thousand, nine hundred twenty".