1561971 has 16 divisors (see below), whose sum is σ = 2230400. Its totient is φ = 969408.

The previous prime is 1561919. The next prime is 1562051. The reversal of 1561971 is 1791651.

It is not a de Polignac number, because 1561971 - 2¹⁴ = 1545587 is a prime.

It is a Duffinian number.

1561971 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1562971) 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, 3615 + ... + 4023.

It is an arithmetic number, because the mean of its divisors is an integer number (139400).

2^1561971 is an apocalyptic number.

1561971 is a deficient number, since it is larger than the sum of its proper divisors (668429).

1561971 is a wasteful number, since it uses less digits than its factorization.

1561971 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 498.

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

The square root of 1561971 is about 1249.7883820871. The cubic root of 1561971 is about 116.0266238929.

The spelling of 1561971 in words is "one million, five hundred sixty-one thousand, nine hundred seventy-one".