1561171340 has 48 divisors (see below), whose sum is σ = 3389904000. Its totient is φ = 603470592.

The previous prime is 1561171321. The next prime is 1561171343. The reversal of 1561171340 is 431711651.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (1561171343) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 103181 + ... + 117339.

It is an arithmetic number, because the mean of its divisors is an integer number (70623000).

Almost surely, 2^1561171340 is an apocalyptic number.

1561171340 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 1561171340, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1694952000).

1561171340 is an abundant number, since it is smaller than the sum of its proper divisors (1828732660).

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

1561171340 is a wasteful number, since it uses less digits than its factorization.

1561171340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14354 (or 14352 counting only the distinct ones).

The product of its (nonzero) digits is 2520, while the sum is 29.

The square root of 1561171340 is about 39511.6608104494. The cubic root of 1561171340 is about 1160.0682034809.

Adding to 1561171340 its reverse (431711651), we get a palindrome (1992882991).

The spelling of 1561171340 in words is "one billion, five hundred sixty-one million, one hundred seventy-one thousand, three hundred forty".