139531281 has 4 divisors (see below), whose sum is σ = 186041712. Its totient is φ = 93020852.

The previous prime is 139531277. The next prime is 139531313. The reversal of 139531281 is 182135931.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 139531281 - 2² = 139531277 is a prime.

It is a super-2 number, since 2×139531281² = 38937956755001922, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (139531261) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 23255211 + ... + 23255216.

It is an arithmetic number, because the mean of its divisors is an integer number (46510428).

Almost surely, 2^139531281 is an apocalyptic number.

It is an amenable number.

139531281 is a deficient number, since it is larger than the sum of its proper divisors (46510431).

139531281 is an equidigital number, since it uses as much as digits as its factorization.

139531281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46510430.

The product of its digits is 6480, while the sum is 33.

The square root of 139531281 is about 11812.3359671151. The cubic root of 139531281 is about 518.6692811746.

The spelling of 139531281 in words is "one hundred thirty-nine million, five hundred thirty-one thousand, two hundred eighty-one".