1643445245 has 16 divisors (see below), whose sum is σ = 2126398512. Its totient is φ = 1212157440.

The previous prime is 1643445239. The next prime is 1643445311. The reversal of 1643445245 is 5425443461.

It can be written as a sum of positive squares in 8 ways, for example, as 109704676 + 1533740569 = 10474^2 + 39163^2 .

It is not a de Polignac number, because 1643445245 - 2⁸ = 1643444989 is a prime.

It is a super-2 number, since 2×1643445245² = 5401824546626220050, 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 = 1643445199 and 1643445208.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 40625 + ... + 70265.

It is an arithmetic number, because the mean of its divisors is an integer number (132899907).

Almost surely, 2^1643445245 is an apocalyptic number.

It is an amenable number.

1643445245 is a deficient number, since it is larger than the sum of its proper divisors (482953267).

1643445245 is a wasteful number, since it uses less digits than its factorization.

1643445245 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30512.

The product of its digits is 230400, while the sum is 38.

The square root of 1643445245 is about 40539.4282766790. The cubic root of 1643445245 is about 1180.0989204154.

The spelling of 1643445245 in words is "one billion, six hundred forty-three million, four hundred forty-five thousand, two hundred forty-five".