139955981 has 16 divisors (see below), whose sum is σ = 156214656. Its totient is φ = 125356000.

The previous prime is 139955953. The next prime is 139955993. The reversal of 139955981 is 189559931.

It is a happy number.

139955981 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 139955981 - 2¹⁸ = 139693837 is a prime.

It is a super-2 number, since 2×139955981² = 39175353235344722, 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 (139955911) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 93761 + ... + 95241.

It is an arithmetic number, because the mean of its divisors is an integer number (9763416).

Almost surely, 2^139955981 is an apocalyptic number.

139955981 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

139955981 is a deficient number, since it is larger than the sum of its proper divisors (16258675).

139955981 is an equidigital number, since it uses as much as digits as its factorization.

139955981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1585 (or 1563 counting only the distinct ones).

The product of its digits is 437400, while the sum is 50.

The square root of 139955981 is about 11830.2992777021. The cubic root of 139955981 is about 519.1949834333.

The spelling of 139955981 in words is "one hundred thirty-nine million, nine hundred fifty-five thousand, nine hundred eighty-one".