139971721 has 8 divisors (see below), whose sum is σ = 146689920. Its totient is φ = 133306272.

The previous prime is 139971707. The next prime is 139971731. The reversal of 139971721 is 127179931.

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 139971721 - 2¹¹ = 139969673 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (139971731) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7701 + ... + 18418.

It is an arithmetic number, because the mean of its divisors is an integer number (18336240).

Almost surely, 2^139971721 is an apocalyptic number.

It is an amenable number.

139971721 is a deficient number, since it is larger than the sum of its proper divisors (6718199).

139971721 is a wasteful number, since it uses less digits than its factorization.

139971721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26375.

The product of its digits is 23814, while the sum is 40.

The square root of 139971721 is about 11830.9644999890. The cubic root of 139971721 is about 519.2144462735.

The spelling of 139971721 in words is "one hundred thirty-nine million, nine hundred seventy-one thousand, seven hundred twenty-one".