645549043 has 2 divisors, whose sum is σ = 645549044. Its totient is φ = 645549042.

The previous prime is 645549029. The next prime is 645549049. The reversal of 645549043 is 340945546.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-645549043 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 645548987 and 645549005.

It is not a weakly prime, because it can be changed into another prime (645549049) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322774521 + 322774522.

It is an arithmetic number, because the mean of its divisors is an integer number (322774522).

Almost surely, 2^645549043 is an apocalyptic number.

645549043 is a deficient number, since it is larger than the sum of its proper divisors (1).

645549043 is an equidigital number, since it uses as much as digits as its factorization.

645549043 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 259200, while the sum is 40.

The square root of 645549043 is about 25407.6571725927. The cubic root of 645549043 is about 864.2573478046.

The spelling of 645549043 in words is "six hundred forty-five million, five hundred forty-nine thousand, forty-three".