1561594720 has 144 divisors (see below), whose sum is σ = 4310923680. Its totient is φ = 532998144.

The previous prime is 1561594711. The next prime is 1561594759. The reversal of 1561594720 is 274951651.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3206317 + ... + 3206803.

It is an arithmetic number, because the mean of its divisors is an integer number (29936970).

Almost surely, 2^1561594720 is an apocalyptic number.

1561594720 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 1561594720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2155461840).

1561594720 is an abundant number, since it is smaller than the sum of its proper divisors (2749328960).

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

1561594720 is a wasteful number, since it uses less digits than its factorization.

1561594720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 925 (or 910 counting only the distinct ones).

The product of its (nonzero) digits is 75600, while the sum is 40.

The square root of 1561594720 is about 39517.0181061274. The cubic root of 1561594720 is about 1160.1730617736.

The spelling of 1561594720 in words is "one billion, five hundred sixty-one million, five hundred ninety-four thousand, seven hundred twenty".