130821981 has 4 divisors (see below), whose sum is σ = 174429312. Its totient is φ = 87214652.

The previous prime is 130821979. The next prime is 130821983. The reversal of 130821981 is 189128031.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 189128031 = 3 ⋅63042677.

It is an interprime number because it is at equal distance from previous prime (130821979) and next prime (130821983).

It is a cyclic number.

It is not a de Polignac number, because 130821981 - 2¹ = 130821979 is a prime.

It is a super-2 number, since 2×130821981² = 34228781425528722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (130821983) 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 in 3 ways as a sum of consecutive naturals, for example, 21803661 + ... + 21803666.

It is an arithmetic number, because the mean of its divisors is an integer number (43607328).

Almost surely, 2^130821981 is an apocalyptic number.

It is an amenable number.

130821981 is a deficient number, since it is larger than the sum of its proper divisors (43607331).

130821981 is an equidigital number, since it uses as much as digits as its factorization.

130821981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43607330.

The product of its (nonzero) digits is 3456, while the sum is 33.

The square root of 130821981 is about 11437.7437023217. The cubic root of 130821981 is about 507.6451489342.

The spelling of 130821981 in words is "one hundred thirty million, eight hundred twenty-one thousand, nine hundred eighty-one".