1671581 has 2 divisors, whose sum is σ = 1671582. Its totient is φ = 1671580.

The previous prime is 1671577. The next prime is 1671599. The reversal of 1671581 is 1851761.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1666681 + 4900 = 1291^2 + 70^2 .

It is an emirp because it is prime and its reverse (1851761) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1671581 - 2² = 1671577 is a prime.

It is a super-2 number, since 2×1671581² = 5588366079122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1671511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 835790 + 835791.

It is an arithmetic number, because the mean of its divisors is an integer number (835791).

2^1671581 is an apocalyptic number.

It is an amenable number.

1671581 is a deficient number, since it is larger than the sum of its proper divisors (1).

1671581 is an equidigital number, since it uses as much as digits as its factorization.

1671581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1680, while the sum is 29.

The square root of 1671581 is about 1292.8963608890. The cubic root of 1671581 is about 118.6795275306.

The spelling of 1671581 in words is "one million, six hundred seventy-one thousand, five hundred eighty-one".