1645032481 has 3 divisors (see below), whose sum is σ = 1645073041. Its totient is φ = 1644991922.

The previous prime is 1645032461. The next prime is 1645032491. The reversal of 1645032481 is 1842305461.

The square root of 1645032481 is 40559.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1842305461 = 241 ⋅7644421.

It is not a de Polignac number, because 1645032481 - 2⁵ = 1645032449 is a prime.

It is a super-2 number, since 2×1645032481² = 5412263727090030722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1645032401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 20280 + ... + 60838.

Almost surely, 2^1645032481 is an apocalyptic number.

1645032481 is the 40559-th square number.

1645032481 is the 20280-th centered octagonal number.

It is an amenable number.

1645032481 is a deficient number, since it is larger than the sum of its proper divisors (40560).

1645032481 is an frugal number, since it uses more digits than its factorization.

1645032481 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81118 (or 40559 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 34.

The cubic root of 1645032481 is about 1180.4787105359.

The spelling of 1645032481 in words is "one billion, six hundred forty-five million, thirty-two thousand, four hundred eighty-one".