1561712640 has 192 divisors, whose sum is σ = 5171493600. Its totient is φ = 401866752.

The previous prime is 1561712629. The next prime is 1561712683. The reversal of 1561712640 is 462171651.

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

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, 890004 + ... + 891756.

Almost surely, 2^1561712640 is an apocalyptic number.

1561712640 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 1561712640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2585746800).

1561712640 is an abundant number, since it is smaller than the sum of its proper divisors (3609780960).

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

1561712640 is a wasteful number, since it uses less digits than its factorization.

1561712640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1812 (or 1792 counting only the distinct ones).

The product of its (nonzero) digits is 10080, while the sum is 33.

The square root of 1561712640 is about 39518.5100933727. The cubic root of 1561712640 is about 1160.2022635808.

The spelling of 1561712640 in words is "one billion, five hundred sixty-one million, seven hundred twelve thousand, six hundred forty".