140591981 has 2 divisors, whose sum is σ = 140591982. Its totient is φ = 140591980.

The previous prime is 140591977. The next prime is 140592017. The reversal of 140591981 is 189195041.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 113081956 + 27510025 = 10634^2 + 5245^2 .

It is a cyclic number.

It is not a de Polignac number, because 140591981 - 2² = 140591977 is a prime.

It is a super-2 number, since 2×140591981² = 39532210243008722, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (140590981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 70295990 + 70295991.

It is an arithmetic number, because the mean of its divisors is an integer number (70295991).

Almost surely, 2^140591981 is an apocalyptic number.

It is an amenable number.

140591981 is a deficient number, since it is larger than the sum of its proper divisors (1).

140591981 is an equidigital number, since it uses as much as digits as its factorization.

140591981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12960, while the sum is 38.

The square root of 140591981 is about 11857.1489406181. The cubic root of 140591981 is about 519.9802519621.

The spelling of 140591981 in words is "one hundred forty million, five hundred ninety-one thousand, nine hundred eighty-one".