139198121 has 2 divisors, whose sum is σ = 139198122. Its totient is φ = 139198120.

The previous prime is 139198117. The next prime is 139198151. The reversal of 139198121 is 121891931.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 119661721 + 19536400 = 10939^2 + 4420^2 .

It is a cyclic number.

It is not a de Polignac number, because 139198121 - 2² = 139198117 is a prime.

It is a super-2 number, since 2×139198121² = 38752233779861282, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (139198151) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69599060 + 69599061.

It is an arithmetic number, because the mean of its divisors is an integer number (69599061).

Almost surely, 2^139198121 is an apocalyptic number.

It is an amenable number.

139198121 is a deficient number, since it is larger than the sum of its proper divisors (1).

139198121 is an equidigital number, since it uses as much as digits as its factorization.

139198121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3888, while the sum is 35.

The square root of 139198121 is about 11798.2253326507. The cubic root of 139198121 is about 518.2561418625.

The spelling of 139198121 in words is "one hundred thirty-nine million, one hundred ninety-eight thousand, one hundred twenty-one".