139726121 has 2 divisors, whose sum is σ = 139726122. Its totient is φ = 139726120.

The previous prime is 139726117. The next prime is 139726123. The reversal of 139726121 is 121627931.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 116877721 + 22848400 = 10811^2 + 4780^2 .

It is an emirp because it is prime and its reverse (121627931) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 139726121 - 2² = 139726117 is a prime.

Together with 139726123, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (139726123) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69863060 + 69863061.

It is an arithmetic number, because the mean of its divisors is an integer number (69863061).

Almost surely, 2^139726121 is an apocalyptic number.

It is an amenable number.

139726121 is a deficient number, since it is larger than the sum of its proper divisors (1).

139726121 is an equidigital number, since it uses as much as digits as its factorization.

139726121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4536, while the sum is 32.

The square root of 139726121 is about 11820.5804003018. The cubic root of 139726121 is about 518.9105903155.

The spelling of 139726121 in words is "one hundred thirty-nine million, seven hundred twenty-six thousand, one hundred twenty-one".