645682426 has 4 divisors (see below), whose sum is σ = 968523642. Its totient is φ = 322841212.

The previous prime is 645682421. The next prime is 645682469. The reversal of 645682426 is 624286546.

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

It can be written as a sum of positive squares in only one way, i.e., 626751225 + 18931201 = 25035^2 + 4351^2 .

It is not an unprimeable number, because it can be changed into a prime (645682421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161420605 + ... + 161420608.

Almost surely, 2^645682426 is an apocalyptic number.

645682426 is a deficient number, since it is larger than the sum of its proper divisors (322841216).

645682426 is a wasteful number, since it uses less digits than its factorization.

645682426 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 322841215.

The product of its digits is 552960, while the sum is 43.

The square root of 645682426 is about 25410.2818953273. The cubic root of 645682426 is about 864.3168678367.

The spelling of 645682426 in words is "six hundred forty-five million, six hundred eighty-two thousand, four hundred twenty-six".