42251381 has 2 divisors, whose sum is σ = 42251382. Its totient is φ = 42251380.

The previous prime is 42251371. The next prime is 42251387. The reversal of 42251381 is 18315224.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 41809156 + 442225 = 6466^2 + 665^2 .

It is a cyclic number.

It is not a de Polignac number, because 42251381 - 2⁶ = 42251317 is a prime.

It is a super-2 number, since 2×42251381² = 3570358392814322, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 42251381.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42251387) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21125690 + 21125691.

It is an arithmetic number, because the mean of its divisors is an integer number (21125691).

Almost surely, 2^42251381 is an apocalyptic number.

It is an amenable number.

42251381 is a deficient number, since it is larger than the sum of its proper divisors (1).

42251381 is an equidigital number, since it uses as much as digits as its factorization.

42251381 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 42251381 is about 6500.1062299012. The cubic root of 42251381 is about 348.2947831445.

The spelling of 42251381 in words is "forty-two million, two hundred fifty-one thousand, three hundred eighty-one".