42513281 has 2 divisors, whose sum is σ = 42513282. Its totient is φ = 42513280.

The previous prime is 42513227. The next prime is 42513287. The reversal of 42513281 is 18231524.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 23232400 + 19280881 = 4820^2 + 4391^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-42513281 is a prime.

It is a super-2 number, since 2×42513281² = 3614758122769922, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 42513281.

It is not a weakly prime, because it can be changed into another prime (42513287) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21256640 + 21256641.

It is an arithmetic number, because the mean of its divisors is an integer number (21256641).

Almost surely, 2^42513281 is an apocalyptic number.

It is an amenable number.

42513281 is a deficient number, since it is larger than the sum of its proper divisors (1).

42513281 is an equidigital number, since it uses as much as digits as its factorization.

42513281 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1920, while the sum is 26.

The square root of 42513281 is about 6520.2209318397. The cubic root of 42513281 is about 349.0129496047.

The spelling of 42513281 in words is "forty-two million, five hundred thirteen thousand, two hundred eighty-one".