1561717807572 has 192 divisors, whose sum is σ = 4008878818560. Its totient is φ = 470319353856.

The previous prime is 1561717807571. The next prime is 1561717807607. The reversal of 1561717807572 is 2757087171651.

It is a hoax number, since the sum of its digits (57) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1561717807571) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 479494168 + ... + 479497424.

It is an arithmetic number, because the mean of its divisors is an integer number (20879577180).

Almost surely, 2^{1561717807572} is an apocalyptic number.

1561717807572 is a gapful number since it is divisible by the number (12) 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 1561717807572, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2004439409280).

1561717807572 is an abundant number, since it is smaller than the sum of its proper divisors (2447161010988).

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

1561717807572 is a wasteful number, since it uses less digits than its factorization.

1561717807572 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3722 (or 3720 counting only the distinct ones).

The product of its (nonzero) digits is 5762400, while the sum is 57.

The spelling of 1561717807572 in words is "one trillion, five hundred sixty-one billion, seven hundred seventeen million, eight hundred seven thousand, five hundred seventy-two".