1001561 has 8 divisors (see below), whose sum is σ = 1106784. Its totient is φ = 898720.

The previous prime is 1001551. The next prime is 1001563. The reversal of 1001561 is 1651001.

1001561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1001561 - 2¹⁰ = 1000537 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1001563) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 365 + ... + 1461.

It is an arithmetic number, because the mean of its divisors is an integer number (138348).

2^1001561 is an apocalyptic number.

1001561 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1001561 is a deficient number, since it is larger than the sum of its proper divisors (105223).

1001561 is a wasteful number, since it uses less digits than its factorization.

1001561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1191.

The product of its (nonzero) digits is 30, while the sum is 14.

The square root of 1001561 is about 1000.7801956474. The cubic root of 1001561 is about 100.0520062821.

Adding to 1001561 its reverse (1651001), we get a palindrome (2652562).

It can be divided in two parts, 100 and 1561, that added together give a palindrome (1661).

The spelling of 1001561 in words is "one million, one thousand, five hundred sixty-one".