1971509540 has 384 divisors, whose sum is σ = 6015098880. Its totient is φ = 522547200.

The previous prime is 1971509513. The next prime is 1971509587. The reversal of 1971509540 is 459051791.

It is a super-2 number, since 2×1971509540² = 7773699732622023200, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 27006944 + ... + 27007016.

It is an arithmetic number, because the mean of its divisors is an integer number (15664320).

Almost surely, 2^1971509540 is an apocalyptic number.

1971509540 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 1971509540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3007549440).

1971509540 is an abundant number, since it is smaller than the sum of its proper divisors (4043589340).

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

1971509540 is a wasteful number, since it uses less digits than its factorization.

1971509540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 203 (or 201 counting only the distinct ones).

The product of its (nonzero) digits is 56700, while the sum is 41.

The square root of 1971509540 is about 44401.6839770746. The cubic root of 1971509540 is about 1253.9097932630.

The spelling of 1971509540 in words is "one billion, nine hundred seventy-one million, five hundred nine thousand, five hundred forty".