645682043 has 4 divisors (see below), whose sum is σ = 666510528. Its totient is φ = 624853560.

The previous prime is 645682021. The next prime is 645682069. The reversal of 645682043 is 340286546.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 340286546 = 2 ⋅170143273.

It is a cyclic number.

It is not a de Polignac number, because 645682043 - 2⁶ = 645681979 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 645681988 and 645682006.

It is not an unprimeable number, because it can be changed into a prime (645682003) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10414196 + ... + 10414257.

It is an arithmetic number, because the mean of its divisors is an integer number (166627632).

Almost surely, 2^645682043 is an apocalyptic number.

645682043 is a deficient number, since it is larger than the sum of its proper divisors (20828485).

645682043 is a wasteful number, since it uses less digits than its factorization.

645682043 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20828484.

The product of its (nonzero) digits is 138240, while the sum is 38.

The square root of 645682043 is about 25410.2743590068. The cubic root of 645682043 is about 864.3166969408.

The spelling of 645682043 in words is "six hundred forty-five million, six hundred eighty-two thousand, forty-three".