139447721 has 8 divisors (see below), whose sum is σ = 159441984. Its totient is φ = 119471760.

The previous prime is 139447699. The next prime is 139447723. The reversal of 139447721 is 127744931.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 139447721 - 2¹⁸ = 139185577 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (139447723) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22286 + ... + 27848.

It is an arithmetic number, because the mean of its divisors is an integer number (19930248).

Almost surely, 2^139447721 is an apocalyptic number.

It is an amenable number.

139447721 is a deficient number, since it is larger than the sum of its proper divisors (19994263).

139447721 is an equidigital number, since it uses as much as digits as its factorization.

139447721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9151.

The product of its digits is 42336, while the sum is 38.

The square root of 139447721 is about 11808.7984570828. The cubic root of 139447721 is about 518.5657233695.

The spelling of 139447721 in words is "one hundred thirty-nine million, four hundred forty-seven thousand, seven hundred twenty-one".