645946 has 32 divisors (see below), whose sum is σ = 1203840. Its totient is φ = 254016.

The previous prime is 645941. The next prime is 645973. The reversal of 645946 is 649546.

It is not an unprimeable number, because it can be changed into a prime (645941) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15001 + ... + 15043.

It is an arithmetic number, because the mean of its divisors is an integer number (37620).

2⁶⁴⁵⁹⁴⁶ is an apocalyptic number.

645946 is a deficient number, since it is larger than the sum of its proper divisors (557894).

645946 is a wasteful number, since it uses less digits than its factorization.

645946 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 118.

The product of its digits is 25920, while the sum is 34.

The square root of 645946 is about 803.7076582937. The cubic root of 645946 is about 86.4434459423.

Subtracting from 645946 its product of digits (25920), we obtain a palindrome (620026).

Subtracting 645946 from its reverse (649546), we obtain a square (3600 = 60²).

The spelling of 645946 in words is "six hundred forty-five thousand, nine hundred forty-six".