139491 has 12 divisors (see below), whose sum is σ = 219960. Its totient is φ = 84480.

The previous prime is 139487. The next prime is 139493. The reversal of 139491 is 194931.

It is not a de Polignac number, because 139491 - 2² = 139487 is a prime.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 139491.

It is not an unprimeable number, because it can be changed into a prime (139493) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 606 + ... + 803.

It is an arithmetic number, because the mean of its divisors is an integer number (18330).

2¹³⁹⁴⁹¹ is an apocalyptic number.

139491 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

139491 is a deficient number, since it is larger than the sum of its proper divisors (80469).

139491 is a wasteful number, since it uses less digits than its factorization.

139491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1426 (or 1423 counting only the distinct ones).

The product of its digits is 972, while the sum is 27.

The square root of 139491 is about 373.4849394554. The cubic root of 139491 is about 51.8619365180.

It can be divided in two parts, 1394 and 91, that added together give a triangular number (1485 = T₅₄).

The spelling of 139491 in words is "one hundred thirty-nine thousand, four hundred ninety-one".