1561995264 has 192 divisors, whose sum is σ = 4402944000. Its totient is φ = 491765760.

The previous prime is 1561995229. The next prime is 1561995307. The reversal of 1561995264 is 4625991651.

It is a tau number, because it is divible by the number of its divisors (192).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11237307 + ... + 11237445.

It is an arithmetic number, because the mean of its divisors is an integer number (22932000).

Almost surely, 2^1561995264 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1561995264, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2201472000).

1561995264 is an abundant number, since it is smaller than the sum of its proper divisors (2840948736).

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

1561995264 is a wasteful number, since it uses less digits than its factorization.

1561995264 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 254 (or 234 counting only the distinct ones).

The product of its digits is 583200, while the sum is 48.

The square root of 1561995264 is about 39522.0857749183. The cubic root of 1561995264 is about 1160.2722468411.

The spelling of 1561995264 in words is "one billion, five hundred sixty-one million, nine hundred ninety-five thousand, two hundred sixty-four".