1971889920 has 1440 divisors, whose sum is σ = 9972103680. Its totient is φ = 358318080.

The previous prime is 1971889919. The next prime is 1971889937. The reversal of 1971889920 is 299881791.

It is a tau number, because it is divible by the number of its divisors (1440).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 103783671 + ... + 103783689.

It is an arithmetic number, because the mean of its divisors is an integer number (6925072).

Almost surely, 2^1971889920 is an apocalyptic number.

1971889920 is a gapful number since it is divisible by the number (10) 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 1971889920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4986051840).

1971889920 is an abundant number, since it is smaller than the sum of its proper divisors (8000213760).

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

1971889920 is a wasteful number, since it uses less digits than its factorization.

1971889920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83 (or 60 counting only the distinct ones).

The product of its (nonzero) digits is 653184, while the sum is 54.

The square root of 1971889920 is about 44405.9671665870. The cubic root of 1971889920 is about 1253.9904305490.

The spelling of 1971889920 in words is "one billion, nine hundred seventy-one million, eight hundred eighty-nine thousand, nine hundred twenty".