1561320 has 48 divisors (see below), whose sum is σ = 5075460. Its totient is φ = 416256.

The previous prime is 1561303. The next prime is 1561337. The reversal of 1561320 is 231651.

It is an interprime number because it is at equal distance from previous prime (1561303) and next prime (1561337).

It can be written as a sum of positive squares in 2 ways, for example, as 1313316 + 248004 = 1146^2 + 498^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 1561293 and 1561302.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1809 + ... + 2528.

2^1561320 is an apocalyptic number.

1561320 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1561320 is an abundant number, since it is smaller than the sum of its proper divisors (3514140).

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

1561320 is a wasteful number, since it uses less digits than its factorization.

1561320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4354 (or 4347 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 18.

The square root of 1561320 is about 1249.5279108527. The cubic root of 1561320 is about 116.0105024181.

Adding to 1561320 its reverse (231651), we get a palindrome (1792971).

It can be divided in two parts, 1561 and 320, that added together give a palindrome (1881).

The spelling of 1561320 in words is "one million, five hundred sixty-one thousand, three hundred twenty".