195401981 has 2 divisors, whose sum is σ = 195401982. Its totient is φ = 195401980.

The previous prime is 195401963. The next prime is 195402013. The reversal of 195401981 is 189104591.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 195160900 + 241081 = 13970^2 + 491^2 .

It is a cyclic number.

It is not a de Polignac number, because 195401981 - 2⁶ = 195401917 is a prime.

It is a super-2 number, since 2×195401981² = 76363868357448722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (195401081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 97700990 + 97700991.

It is an arithmetic number, because the mean of its divisors is an integer number (97700991).

Almost surely, 2^195401981 is an apocalyptic number.

It is an amenable number.

195401981 is a deficient number, since it is larger than the sum of its proper divisors (1).

195401981 is an equidigital number, since it uses as much as digits as its factorization.

195401981 is an odious number, because the sum of its binary digits is odd.

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

The square root of 195401981 is about 13978.6258623657. The cubic root of 195401981 is about 580.2871952627.

The spelling of 195401981 in words is "one hundred ninety-five million, four hundred one thousand, nine hundred eighty-one".