139347981 has 12 divisors (see below), whose sum is σ = 201395740. Its totient is φ = 92845440.

The previous prime is 139347931. The next prime is 139347991. The reversal of 139347981 is 189743931.

139347981 is a `hidden beast` number, since 13 + 93 + 479 + 81 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 88454025 + 50893956 = 9405^2 + 7134^2 .

It is not a de Polignac number, because 139347981 - 2⁹ = 139347469 is a prime.

It is a super-2 number, since 2×139347981² = 38835719617552722, 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 (139347931) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 18261 + ... + 24741.

Almost surely, 2^139347981 is an apocalyptic number.

It is an amenable number.

139347981 is a deficient number, since it is larger than the sum of its proper divisors (62047759).

139347981 is a wasteful number, since it uses less digits than its factorization.

139347981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8876 (or 8873 counting only the distinct ones).

The product of its digits is 163296, while the sum is 45.

The square root of 139347981 is about 11804.5745793739. The cubic root of 139347981 is about 518.4420591483.

The spelling of 139347981 in words is "one hundred thirty-nine million, three hundred forty-seven thousand, nine hundred eighty-one".