145669981 has 2 divisors, whose sum is σ = 145669982. Its totient is φ = 145669980.

The previous prime is 145669963. The next prime is 145670051. The reversal of 145669981 is 189966541.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 121992025 + 23677956 = 11045^2 + 4866^2 .

It is a cyclic number.

It is not a de Polignac number, because 145669981 - 2¹⁵ = 145637213 is a prime.

It is a super-2 number, since 2×145669981² = 42439486729080722, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (145669921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 72834990 + 72834991.

It is an arithmetic number, because the mean of its divisors is an integer number (72834991).

Almost surely, 2^145669981 is an apocalyptic number.

It is an amenable number.

145669981 is a deficient number, since it is larger than the sum of its proper divisors (1).

145669981 is an equidigital number, since it uses as much as digits as its factorization.

145669981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 466560, while the sum is 49.

The square root of 145669981 is about 12069.3819642930. The cubic root of 145669981 is about 526.1666945541.

The spelling of 145669981 in words is "one hundred forty-five million, six hundred sixty-nine thousand, nine hundred eighty-one".