1645304431 has 4 divisors (see below), whose sum is σ = 1658259712. Its totient is φ = 1632349152.

The previous prime is 1645304417. The next prime is 1645304467. The reversal of 1645304431 is 1344035461.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1344035461 = 1811 ⋅742151.

It is a cyclic number.

It is not a de Polignac number, because 1645304431 - 2⁷ = 1645304303 is a prime.

It is a super-2 number, since 2×1645304431² = 5414053341336467522, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1645304393 and 1645304402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1640304431) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6477450 + ... + 6477703.

It is an arithmetic number, because the mean of its divisors is an integer number (414564928).

Almost surely, 2^1645304431 is an apocalyptic number.

1645304431 is a deficient number, since it is larger than the sum of its proper divisors (12955281).

1645304431 is a wasteful number, since it uses less digits than its factorization.

1645304431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12955280.

The product of its (nonzero) digits is 17280, while the sum is 31.

The square root of 1645304431 is about 40562.3523849394. The cubic root of 1645304431 is about 1180.5437575791.

Adding to 1645304431 its reverse (1344035461), we get a palindrome (2989339892).

The spelling of 1645304431 in words is "one billion, six hundred forty-five million, three hundred four thousand, four hundred thirty-one".