645406406 has 4 divisors (see below), whose sum is σ = 968109612. Its totient is φ = 322703202.

The previous prime is 645406367. The next prime is 645406409. The reversal of 645406406 is 604604546.

645406406 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645406409) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161351600 + ... + 161351603.

It is an arithmetic number, because the mean of its divisors is an integer number (242027403).

Almost surely, 2^645406406 is an apocalyptic number.

645406406 is a deficient number, since it is larger than the sum of its proper divisors (322703206).

645406406 is a wasteful number, since it uses less digits than its factorization.

645406406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 322703205.

The product of its (nonzero) digits is 69120, while the sum is 35.

The square root of 645406406 is about 25404.8500487604. The cubic root of 645406406 is about 864.1936892506.

The spelling of 645406406 in words is "six hundred forty-five million, four hundred six thousand, four hundred six".