139668481 has 4 divisors (see below), whose sum is σ = 147884292. Its totient is φ = 131452672.

The previous prime is 139668479. The next prime is 139668511. The reversal of 139668481 is 184866931.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 106502400 + 33166081 = 10320^2 + 5759^2 .

It is a cyclic number.

It is not a de Polignac number, because 139668481 - 2¹ = 139668479 is a prime.

It is a super-2 number, since 2×139668481² = 39014569169694722, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (139668421) 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, 4107880 + ... + 4107913.

It is an arithmetic number, because the mean of its divisors is an integer number (36971073).

Almost surely, 2^139668481 is an apocalyptic number.

It is an amenable number.

139668481 is a deficient number, since it is larger than the sum of its proper divisors (8215811).

139668481 is an equidigital number, since it uses as much as digits as its factorization.

139668481 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8215810.

The product of its digits is 248832, while the sum is 46.

The square root of 139668481 is about 11818.1420282547. The cubic root of 139668481 is about 518.8392266125.

The spelling of 139668481 in words is "one hundred thirty-nine million, six hundred sixty-eight thousand, four hundred eighty-one".