181021445 has 18 divisors (see below), whose sum is σ = 239206086. Its totient is φ = 131411280.

The previous prime is 181021411. The next prime is 181021453. The reversal of 181021445 is 544120181.

It can be written as a sum of positive squares in only one way, i.e., 144817156 + 36204289 = 12034^2 + 6017^2 .

It is not a de Polignac number, because 181021445 - 2¹² = 181017349 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 330662 + ... + 331208.

It is an arithmetic number, because the mean of its divisors is an integer number (13289227).

Almost surely, 2^181021445 is an apocalyptic number.

It is an amenable number.

181021445 is a deficient number, since it is larger than the sum of its proper divisors (58184641).

181021445 is an frugal number, since it uses more digits than its factorization.

181021445 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1121 (or 563 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 26.

The square root of 181021445 is about 13454.4210206162. The cubic root of 181021445 is about 565.6876218326.

Multiplying 181021445 by its product of nonzero digits (1280), we get a square (231707449600 = 481360²).

The spelling of 181021445 in words is "one hundred eighty-one million, twenty-one thousand, four hundred forty-five".