645080537 has 4 divisors (see below), whose sum is σ = 647590836. Its totient is φ = 642570240.

The previous prime is 645080531. The next prime is 645080617. The reversal of 645080537 is 735080546.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 735080546 = 2 ⋅367540273.

It can be written as a sum of positive squares in 2 ways, for example, as 453008656 + 192071881 = 21284^2 + 13859^2 .

It is a cyclic number.

It is not a de Polignac number, because 645080537 - 2⁶ = 645080473 is a prime.

It is a super-2 number, since 2×645080537² = 832257798432416738, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 645080537.

It is not an unprimeable number, because it can be changed into a prime (645080531) 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, 1254764 + ... + 1255277.

It is an arithmetic number, because the mean of its divisors is an integer number (161897709).

Almost surely, 2^645080537 is an apocalyptic number.

It is an amenable number.

645080537 is a deficient number, since it is larger than the sum of its proper divisors (2510299).

645080537 is a wasteful number, since it uses less digits than its factorization.

645080537 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2510298.

The product of its (nonzero) digits is 100800, while the sum is 38.

The square root of 645080537 is about 25398.4357195478. The cubic root of 645080537 is about 864.0482194918.

Subtracting 645080537 from its reverse (735080546), we obtain a palindrome (90000009).

The spelling of 645080537 in words is "six hundred forty-five million, eighty thousand, five hundred thirty-seven".