1561404 has 24 divisors (see below), whose sum is σ = 3923920. Its totient is φ = 480384.

The previous prime is 1561393. The next prime is 1561421. The reversal of 1561404 is 4041651.

It is a Smith number, since the sum of its digits (21) coincides with the sum of the digits of its prime factors.

1561404 is a modest number, since divided by 1404 gives 156 as remainder.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4849 + ... + 5160.

2^1561404 is an apocalyptic number.

It is an amenable number.

1561404 is an abundant number, since it is smaller than the sum of its proper divisors (2362516).

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

1561404 is a wasteful number, since it uses less digits than its factorization.

1561404 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10029 (or 10027 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 21.

The square root of 1561404 is about 1249.5615230952. The cubic root of 1561404 is about 116.0125828602.

It can be divided in two parts, 156 and 1404, that multiplied together give a square (219024 = 468²).

The spelling of 1561404 in words is "one million, five hundred sixty-one thousand, four hundred four".