139027981 has 4 divisors (see below), whose sum is σ = 142785532. Its totient is φ = 135270432.

The previous prime is 139027951. The next prime is 139028003. The reversal of 139027981 is 189720931.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 61763881 + 77264100 = 7859^2 + 8790^2 .

It is a cyclic number.

It is not a de Polignac number, because 139027981 - 2⁵ = 139027949 is a prime.

It is a super-2 number, since 2×139027981² = 38657559001872722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (139027951) 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 3 ways as a sum of consecutive naturals, for example, 1878720 + ... + 1878793.

It is an arithmetic number, because the mean of its divisors is an integer number (35696383).

Almost surely, 2^139027981 is an apocalyptic number.

It is an amenable number.

139027981 is a deficient number, since it is larger than the sum of its proper divisors (3757551).

139027981 is an equidigital number, since it uses as much as digits as its factorization.

139027981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3757550.

The product of its (nonzero) digits is 27216, while the sum is 40.

The square root of 139027981 is about 11791.0127215604. The cubic root of 139027981 is about 518.0449032595.

The spelling of 139027981 in words is "one hundred thirty-nine million, twenty-seven thousand, nine hundred eighty-one".