145579981 has 4 divisors (see below), whose sum is σ = 145605852. Its totient is φ = 145554112.

The previous prime is 145579969. The next prime is 145579991. The reversal of 145579981 is 189975541.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 47748100 + 97831881 = 6910^2 + 9891^2 .

It is a cyclic number.

It is not a de Polignac number, because 145579981 - 2²⁵ = 112025549 is a prime.

It is a super-2 number, since 2×145579981² = 42387061735920722, which contains 22 as substring.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (145579921) 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, 526 + ... + 17071.

It is an arithmetic number, because the mean of its divisors is an integer number (36401463).

Almost surely, 2^145579981 is an apocalyptic number.

It is an amenable number.

145579981 is a deficient number, since it is larger than the sum of its proper divisors (25871).

145579981 is an equidigital number, since it uses as much as digits as its factorization.

145579981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25870.

The product of its digits is 453600, while the sum is 49.

The square root of 145579981 is about 12065.6529454481. The cubic root of 145579981 is about 526.0583108454.

The spelling of 145579981 in words is "one hundred forty-five million, five hundred seventy-nine thousand, nine hundred eighty-one".