1971563328 has 140 divisors (see below), whose sum is σ = 6679358752. Its totient is φ = 563293440.

The previous prime is 1971563317. The next prime is 1971563353. The reversal of 1971563328 is 8233651791.

1971563328 is a `hidden beast` number, since 1 + 9 + 7 + 1 + 5 + 633 + 2 + 8 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 9123 + ... + 63453.

Almost surely, 2^1971563328 is an apocalyptic number.

1971563328 is a gapful number since it is divisible by the number (18) 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 1971563328, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3339679376).

1971563328 is an abundant number, since it is smaller than the sum of its proper divisors (4707795424).

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

1971563328 is an equidigital number, since it uses as much as digits as its factorization.

1971563328 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54362 (or 54343 counting only the distinct ones).

The product of its digits is 272160, while the sum is 45.

The square root of 1971563328 is about 44402.2896706915. The cubic root of 1971563328 is about 1253.9211964857.

The spelling of 1971563328 in words is "one billion, nine hundred seventy-one million, five hundred sixty-three thousand, three hundred twenty-eight".