2021778377928 has 320 divisors, whose sum is σ = 6226473369600. Its totient is φ = 610068412800.

The previous prime is 2021778377897. The next prime is 2021778377929. The reversal of 2021778377928 is 8297738771202.

2021778377928 is a `hidden beast` number, since 2 + 0 + 2 + 177 + 8 + 377 + 92 + 8 = 666.

It is not an unprimeable number, because it can be changed into a prime (2021778377929) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 325932475 + ... + 325938677.

It is an arithmetic number, because the mean of its divisors is an integer number (19457729280).

Almost surely, 2^{2021778377928} 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 2021778377928, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3113236684800).

2021778377928 is an abundant number, since it is smaller than the sum of its proper divisors (4204694991672).

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

2021778377928 is a wasteful number, since it uses less digits than its factorization.

2021778377928 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7414 (or 7401 counting only the distinct ones).

The product of its (nonzero) digits is 33191424, while the sum is 63.

The spelling of 2021778377928 in words is "two trillion, twenty-one billion, seven hundred seventy-eight million, three hundred seventy-seven thousand, nine hundred twenty-eight".