1561650 has 48 divisors (see below), whose sum is σ = 4017600. Its totient is φ = 400960.

The previous prime is 1561639. The next prime is 1561657. The reversal of 1561650 is 561651.

It is an Ulam number.

It is a nialpdrome in base 11.

It is a self number, because there is not a number n which added to its sum of digits gives 1561650.

It is not an unprimeable number, because it can be changed into a prime (1561657) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4171 + ... + 4529.

It is an arithmetic number, because the mean of its divisors is an integer number (83700).

2^1561650 is an apocalyptic number.

1561650 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 1561650, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2008800).

1561650 is an abundant number, since it is smaller than the sum of its proper divisors (2455950).

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

1561650 is a wasteful number, since it uses less digits than its factorization.

1561650 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 403 (or 398 counting only the distinct ones).

The product of its (nonzero) digits is 900, while the sum is 24.

The square root of 1561650 is about 1249.6599537474. The cubic root of 1561650 is about 116.0186751542.

Subtracting from 1561650 its reverse (561651), we obtain a palindrome (999999).

It can be divided in two parts, 1561 and 650, that added together give a triangular number (2211 = T₆₆).

The spelling of 1561650 in words is "one million, five hundred sixty-one thousand, six hundred fifty".