139491909 has 16 divisors (see below), whose sum is σ = 213322240. Its totient is φ = 89994240.

The previous prime is 139491907. The next prime is 139491931. The reversal of 139491909 is 909194931.

It is not a de Polignac number, because 139491909 - 2¹ = 139491907 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (139491907) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 82492 + ... + 84165.

It is an arithmetic number, because the mean of its divisors is an integer number (13332640).

Almost surely, 2^139491909 is an apocalyptic number.

It is an amenable number.

139491909 is a deficient number, since it is larger than the sum of its proper divisors (73830331).

139491909 is a wasteful number, since it uses less digits than its factorization.

139491909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 166697 (or 166691 counting only the distinct ones).

The product of its (nonzero) digits is 78732, while the sum is 45.

The square root of 139491909 is about 11810.6692867085. The cubic root of 139491909 is about 518.6204917135.

The spelling of 139491909 in words is "one hundred thirty-nine million, four hundred ninety-one thousand, nine hundred nine".