3561581 has 2 divisors, whose sum is σ = 3561582. Its totient is φ = 3561580.

The previous prime is 3561541. The next prime is 3561611. The reversal of 3561581 is 1851653.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 3363556 + 198025 = 1834^2 + 445^2 .

It is a cyclic number.

It is not a de Polignac number, because 3561581 - 2¹⁸ = 3299437 is a prime.

It is a super-2 number, since 2×3561581² = 25369718439122, which contains 22 as substring.

It is a Chen prime.

It is an Ulam number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3561511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1780790 + 1780791.

It is an arithmetic number, because the mean of its divisors is an integer number (1780791).

Almost surely, 2^3561581 is an apocalyptic number.

It is an amenable number.

3561581 is a deficient number, since it is larger than the sum of its proper divisors (1).

3561581 is an equidigital number, since it uses as much as digits as its factorization.

3561581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3600, while the sum is 29.

The square root of 3561581 is about 1887.2151440681. The cubic root of 3561581 is about 152.7147346674.

It can be divided in two parts, 35 and 61581, that added together give a palindrome (61616).

The spelling of 3561581 in words is "three million, five hundred sixty-one thousand, five hundred eighty-one".