195400379981 has 2 divisors, whose sum is σ = 195400379982. Its totient is φ = 195400379980.

The previous prime is 195400379959. The next prime is 195400380001. The reversal of 195400379981 is 189973004591.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 150144625225 + 45255754756 = 387485^2 + 212734^2 .

It is a cyclic number.

It is not a de Polignac number, because 195400379981 - 2²⁶ = 195333271117 is a prime.

It is a super-2 number, since 2×195400379981² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (195400378981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 97700189990 + 97700189991.

It is an arithmetic number, because the mean of its divisors is an integer number (97700189991).

Almost surely, 2^195400379981 is an apocalyptic number.

It is an amenable number.

195400379981 is a deficient number, since it is larger than the sum of its proper divisors (1).

195400379981 is an equidigital number, since it uses as much as digits as its factorization.

195400379981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2449440, while the sum is 56.

The spelling of 195400379981 in words is "one hundred ninety-five billion, four hundred million, three hundred seventy-nine thousand, nine hundred eighty-one".