1561601000 has 32 divisors (see below), whose sum is σ = 3654148680. Its totient is φ = 624640000.

The previous prime is 1561600987. The next prime is 1561601023. The reversal of 1561601000 is 1061651.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 1008316516 + 553284484 = 31754^2 + 23522^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 779801 + ... + 781800.

Almost surely, 2^1561601000 is an apocalyptic number.

1561601000 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1561601000 is an abundant number, since it is smaller than the sum of its proper divisors (2092547680).

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

1561601000 is a wasteful number, since it uses less digits than its factorization.

1561601000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1561622 (or 1561608 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 20.

The square root of 1561601000 is about 39517.0975654842. The cubic root of 1561601000 is about 1160.1746169951.

Adding to 1561601000 its reverse (1061651), we get a palindrome (1562662651).

The spelling of 1561601000 in words is "one billion, five hundred sixty-one million, six hundred one thousand".