645894079 has 4 divisors (see below), whose sum is σ = 645963120. Its totient is φ = 645825040.

The previous prime is 645894049. The next prime is 645894103. The reversal of 645894079 is 970498546.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 645894079 - 2¹⁷ = 645763007 is a prime.

It is a super-2 number, since 2×645894079² = 834358322574516482, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645894049) 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, 17782 + ... + 40099.

It is an arithmetic number, because the mean of its divisors is an integer number (161490780).

Almost surely, 2^645894079 is an apocalyptic number.

645894079 is a deficient number, since it is larger than the sum of its proper divisors (69041).

645894079 is a wasteful number, since it uses less digits than its factorization.

645894079 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69040.

The product of its (nonzero) digits is 2177280, while the sum is 52.

The square root of 645894079 is about 25414.4462658544. The cubic root of 645894079 is about 864.4112977844.

The spelling of 645894079 in words is "six hundred forty-five million, eight hundred ninety-four thousand, seventy-nine".