20420977606656 has 240 divisors, whose sum is σ = 60668671956480. Its totient is φ = 6056504197120.

The previous prime is 20420977606643. The next prime is 20420977606727. The reversal of 20420977606656 is 65660677902402.

It is a self number, because there is not a number n which added to its sum of digits gives 20420977606656.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 25009780 + ... + 25813388.

It is an arithmetic number, because the mean of its divisors is an integer number (252786133152).

Almost surely, 2^{20420977606656} 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 20420977606656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30334335978240).

20420977606656 is an abundant number, since it is smaller than the sum of its proper divisors (40247694349824).

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

20420977606656 is an equidigital number, since it uses as much as digits as its factorization.

20420977606656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 803698 (or 803672 counting only the distinct ones).

The product of its (nonzero) digits is 45722880, while the sum is 60.

The spelling of 20420977606656 in words is "twenty trillion, four hundred twenty billion, nine hundred seventy-seven million, six hundred six thousand, six hundred fifty-six".