1630561 has 4 divisors (see below), whose sum is σ = 1716400. Its totient is φ = 1544724.

The previous prime is 1630549. The next prime is 1630597. The reversal of 1630561 is 1650361.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1650361 = 29 ⋅56909.

It is a cyclic number.

It is not a de Polignac number, because 1630561 - 2⁹ = 1630049 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1630501) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 42891 + ... + 42928.

It is an arithmetic number, because the mean of its divisors is an integer number (429100).

2^1630561 is an apocalyptic number.

It is an amenable number.

1630561 is a deficient number, since it is larger than the sum of its proper divisors (85839).

1630561 is an equidigital number, since it uses as much as digits as its factorization.

1630561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85838.

The product of its (nonzero) digits is 540, while the sum is 22.

The square root of 1630561 is about 1276.9342191358. The cubic root of 1630561 is about 117.7006921781.

The spelling of 1630561 in words is "one million, six hundred thirty thousand, five hundred sixty-one".