139257281 has 2 divisors, whose sum is σ = 139257282. Its totient is φ = 139257280.

The previous prime is 139257269. The next prime is 139257299. The reversal of 139257281 is 182752931.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 81360400 + 57896881 = 9020^2 + 7609^2 .

It is a cyclic number.

It is not a de Polignac number, because 139257281 - 2¹⁸ = 138995137 is a prime.

It is a super-2 number, since 2×139257281² = 38785180623025922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (139257211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69628640 + 69628641.

It is an arithmetic number, because the mean of its divisors is an integer number (69628641).

Almost surely, 2^139257281 is an apocalyptic number.

It is an amenable number.

139257281 is a deficient number, since it is larger than the sum of its proper divisors (1).

139257281 is an equidigital number, since it uses as much as digits as its factorization.

139257281 is an evil number, because the sum of its binary digits is even.

The product of its digits is 30240, while the sum is 38.

The square root of 139257281 is about 11800.7322230445. The cubic root of 139257281 is about 518.3295520747.

The spelling of 139257281 in words is "one hundred thirty-nine million, two hundred fifty-seven thousand, two hundred eighty-one".