1561664 has 28 divisors (see below), whose sum is σ = 3339084. Its totient is φ = 720384.

The previous prime is 1561657. The next prime is 1561673. The reversal of 1561664 is 4661651.

It can be written as a sum of positive squares in 2 ways, for example, as 577600 + 984064 = 760^2 + 992^2 .

It is a hoax number, since the sum of its digits (29) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 107 + ... + 1770.

It is an arithmetic number, because the mean of its divisors is an integer number (119253).

2^1561664 is an apocalyptic number.

It is an amenable number.

1561664 is an abundant number, since it is smaller than the sum of its proper divisors (1777420).

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

1561664 is a wasteful number, since it uses less digits than its factorization.

1561664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1902 (or 1892 counting only the distinct ones).

The product of its digits is 4320, while the sum is 29.

The square root of 1561664 is about 1249.6655552587. The cubic root of 1561664 is about 116.0190218509.

The spelling of 1561664 in words is "one million, five hundred sixty-one thousand, six hundred sixty-four".