645545542 has 4 divisors (see below), whose sum is σ = 968318316. Its totient is φ = 322772770.

The previous prime is 645545513. The next prime is 645545567. The reversal of 645545542 is 245545546.

It is a happy number.

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

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a junction number, because it is equal to n+sod(n) for n = 645545495 and 645545504.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161386384 + ... + 161386387.

It is an arithmetic number, because the mean of its divisors is an integer number (242079579).

Almost surely, 2^645545542 is an apocalyptic number.

645545542 is a deficient number, since it is larger than the sum of its proper divisors (322772774).

645545542 is a wasteful number, since it uses less digits than its factorization.

645545542 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 322772773.

The product of its digits is 480000, while the sum is 40.

The square root of 645545542 is about 25407.5882759462. The cubic root of 645545542 is about 864.2557854289.

The spelling of 645545542 in words is "six hundred forty-five million, five hundred forty-five thousand, five hundred forty-two".