139186921 has 8 divisors (see below), whose sum is σ = 144241920. Its totient is φ = 134149008.

The previous prime is 139186919. The next prime is 139186963. The reversal of 139186921 is 129681931.

139186921 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 139186921 - 2¹ = 139186919 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (139186981) 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, 13650 + ... + 21556.

It is an arithmetic number, because the mean of its divisors is an integer number (18030240).

Almost surely, 2^139186921 is an apocalyptic number.

It is an amenable number.

139186921 is a deficient number, since it is larger than the sum of its proper divisors (5054999).

139186921 is an equidigital number, since it uses as much as digits as its factorization.

139186921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8543.

The product of its digits is 23328, while the sum is 40.

The square root of 139186921 is about 11797.7506754466. The cubic root of 139186921 is about 518.2422417121.

The spelling of 139186921 in words is "one hundred thirty-nine million, one hundred eighty-six thousand, nine hundred twenty-one".