1971538400 has 144 divisors (see below), whose sum is σ = 5208979104. Its totient is φ = 724346880.

The previous prime is 1971538351. The next prime is 1971538409. The reversal of 1971538400 is 48351791.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1971538409) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3046877 + ... + 3047523.

It is an arithmetic number, because the mean of its divisors is an integer number (36173466).

Almost surely, 2^1971538400 is an apocalyptic number.

1971538400 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 1971538400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2604489552).

1971538400 is an abundant number, since it is smaller than the sum of its proper divisors (3237440704).

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

1971538400 is a wasteful number, since it uses less digits than its factorization.

1971538400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 973 (or 960 counting only the distinct ones).

The product of its (nonzero) digits is 30240, while the sum is 38.

The square root of 1971538400 is about 44402.0089635593. The cubic root of 1971538400 is about 1253.9159116982.

The spelling of 1971538400 in words is "one billion, nine hundred seventy-one million, five hundred thirty-eight thousand, four hundred".