12720139 has 4 divisors (see below), whose sum is σ = 13389640. Its totient is φ = 12050640.

The previous prime is 12720133. The next prime is 12720157. The reversal of 12720139 is 93102721.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 93102721 = 1201 ⋅77521.

It is a cyclic number.

It is not a de Polignac number, because 12720139 - 2⁵ = 12720107 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12720133) 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, 334722 + ... + 334759.

It is an arithmetic number, because the mean of its divisors is an integer number (3347410).

Almost surely, 2^12720139 is an apocalyptic number.

12720139 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

12720139 is a deficient number, since it is larger than the sum of its proper divisors (669501).

12720139 is an equidigital number, since it uses as much as digits as its factorization.

12720139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 669500.

The product of its (nonzero) digits is 756, while the sum is 25.

The square root of 12720139 is about 3566.5303868045. The cubic root of 12720139 is about 233.4339142336.

The spelling of 12720139 in words is "twelve million, seven hundred twenty thousand, one hundred thirty-nine".