42109261 has 2 divisors, whose sum is σ = 42109262. Its totient is φ = 42109260.

The previous prime is 42109241. The next prime is 42109267. The reversal of 42109261 is 16290124.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 29106025 + 13003236 = 5395^2 + 3606^2 .

It is a cyclic number.

It is not a de Polignac number, because 42109261 - 2⁵ = 42109229 is a prime.

It is a super-2 number, since 2×42109261² = 3546379723932242, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42109267) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21054630 + 21054631.

It is an arithmetic number, because the mean of its divisors is an integer number (21054631).

Almost surely, 2^42109261 is an apocalyptic number.

It is an amenable number.

42109261 is a deficient number, since it is larger than the sum of its proper divisors (1).

42109261 is an equidigital number, since it uses as much as digits as its factorization.

42109261 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 42109261 is about 6489.1648923417. The cubic root of 42109261 is about 347.9038274121.

Adding to 42109261 its reverse (16290124), we get a palindrome (58399385).

The spelling of 42109261 in words is "forty-two million, one hundred nine thousand, two hundred sixty-one".