645090643 has 8 divisors (see below), whose sum is σ = 654634512. Its totient is φ = 635606016.

The previous prime is 645090617. The next prime is 645090701. The reversal of 645090643 is 346090546.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 645090643 - 2¹⁷ = 644959571 is a prime.

It is a super-2 number, since 2×645090643² = 832283875372306898, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (645096643) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7371 + ... + 36667.

It is an arithmetic number, because the mean of its divisors is an integer number (81829314).

Almost surely, 2^645090643 is an apocalyptic number.

645090643 is a deficient number, since it is larger than the sum of its proper divisors (9543869).

645090643 is a wasteful number, since it uses less digits than its factorization.

645090643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29621.

The product of its (nonzero) digits is 77760, while the sum is 37.

The square root of 645090643 is about 25398.6346680289. The cubic root of 645090643 is about 864.0527316032.

The spelling of 645090643 in words is "six hundred forty-five million, ninety thousand, six hundred forty-three".