139830721 has 4 divisors (see below), whose sum is σ = 144652500. Its totient is φ = 135008944.

The previous prime is 139830679. The next prime is 139830749. The reversal of 139830721 is 127038931.

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 110019121 + 29811600 = 10489^2 + 5460^2 .

It is a cyclic number.

It is not a de Polignac number, because 139830721 - 2¹⁷ = 139699649 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (139830751) 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, 2410846 + ... + 2410903.

It is an arithmetic number, because the mean of its divisors is an integer number (36163125).

Almost surely, 2^139830721 is an apocalyptic number.

It is an amenable number.

139830721 is a deficient number, since it is larger than the sum of its proper divisors (4821779).

139830721 is an equidigital number, since it uses as much as digits as its factorization.

139830721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4821778.

The product of its (nonzero) digits is 9072, while the sum is 34.

The square root of 139830721 is about 11825.0040591959. The cubic root of 139830721 is about 519.0400447765.

The spelling of 139830721 in words is "one hundred thirty-nine million, eight hundred thirty thousand, seven hundred twenty-one".