645535537 has 4 divisors (see below), whose sum is σ = 666359296. Its totient is φ = 624711780.

The previous prime is 645535531. The next prime is 645535567. The reversal of 645535537 is 735535546.

It is a happy number.

645535537 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 645535537 - 2⁷ = 645535409 is a prime.

It is a super-2 number, since 2×645535537² = 833432259059756738, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 645535493 and 645535502.

It is not an unprimeable number, because it can be changed into a prime (645535531) 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, 10411833 + ... + 10411894.

It is an arithmetic number, because the mean of its divisors is an integer number (166589824).

Almost surely, 2^645535537 is an apocalyptic number.

It is an amenable number.

645535537 is a deficient number, since it is larger than the sum of its proper divisors (20823759).

645535537 is a wasteful number, since it uses less digits than its factorization.

645535537 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20823758.

The product of its digits is 945000, while the sum is 43.

The square root of 645535537 is about 25407.3913851855. The cubic root of 645535537 is about 864.2513205109.

Subtracting 645535537 from its reverse (735535546), we obtain a palindrome (90000009).

The spelling of 645535537 in words is "six hundred forty-five million, five hundred thirty-five thousand, five hundred thirty-seven".