195657981 has 8 divisors (see below), whose sum is σ = 276223104. Its totient is φ = 122765760.

The previous prime is 195657977. The next prime is 195658003. The reversal of 195657981 is 189756591.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 195657981 - 2² = 195657977 is a prime.

It is a super-2 number, since 2×195657981² = 76564091057992722, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (51), and also a Moran number because the ratio is a prime number: 3836431 = 195657981 / (1 + 9 + 5 + 6 + 5 + 7 + 9 + 8 + 1).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (195657901) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1918165 + ... + 1918266.

It is an arithmetic number, because the mean of its divisors is an integer number (34527888).

Almost surely, 2^195657981 is an apocalyptic number.

It is an amenable number.

195657981 is a deficient number, since it is larger than the sum of its proper divisors (80565123).

195657981 is a wasteful number, since it uses less digits than its factorization.

195657981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3836451.

The product of its digits is 680400, while the sum is 51.

The square root of 195657981 is about 13987.7797022973. The cubic root of 195657981 is about 580.5404999190.

The spelling of 195657981 in words is "one hundred ninety-five million, six hundred fifty-seven thousand, nine hundred eighty-one".