1978621568 has 256 divisors, whose sum is σ = 5331744000. Its totient is φ = 722534400.

The previous prime is 1978621543. The next prime is 1978621571. The reversal of 1978621568 is 8651268791.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 8209928 + ... + 8210168.

It is an arithmetic number, because the mean of its divisors is an integer number (20827125).

Almost surely, 2^1978621568 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 1978621568, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2665872000).

1978621568 is an abundant number, since it is smaller than the sum of its proper divisors (3353122432).

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

1978621568 is a wasteful number, since it uses less digits than its factorization.

1978621568 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 304 (or 278 counting only the distinct ones).

The product of its digits is 1451520, while the sum is 53.

The square root of 1978621568 is about 44481.6992481178. The cubic root of 1978621568 is about 1255.4157695051.

The spelling of 1978621568 in words is "one billion, nine hundred seventy-eight million, six hundred twenty-one thousand, five hundred sixty-eight".