1561791 has 16 divisors (see below), whose sum is σ = 2596608. Its totient is φ = 811200.

The previous prime is 1561759. The next prime is 1561801. The reversal of 1561791 is 1971651.

It is not a de Polignac number, because 1561791 - 2⁵ = 1561759 is a prime.

It is a super-2 number, since 2×1561791² = 4878382255362, which contains 22 as substring.

It is an Ulam number.

It is a nialpdrome in base 11.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1561711) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3150 + ... + 3611.

It is an arithmetic number, because the mean of its divisors is an integer number (162288).

2^1561791 is an apocalyptic number.

1561791 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1561791 is a deficient number, since it is larger than the sum of its proper divisors (1034817).

1561791 is a wasteful number, since it uses less digits than its factorization.

1561791 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6782.

The product of its digits is 1890, while the sum is 30.

The square root of 1561791 is about 1249.7163678211. The cubic root of 1561791 is about 116.0221667904.

The spelling of 1561791 in words is "one million, five hundred sixty-one thousand, seven hundred ninety-one".