645217437 has 12 divisors (see below), whose sum is σ = 873339936. Its totient is φ = 423716040.

The previous prime is 645217429. The next prime is 645217453. The reversal of 645217437 is 734712546.

It is not a de Polignac number, because 645217437 - 2³ = 645217429 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 645217395 and 645217404.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645216437) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 10489 + ... + 37422.

It is an arithmetic number, because the mean of its divisors is an integer number (72778328).

Almost surely, 2^645217437 is an apocalyptic number.

645217437 is a gapful number since it is divisible by the number (67) formed by its first and last digit.

It is an amenable number.

645217437 is a deficient number, since it is larger than the sum of its proper divisors (228122499).

645217437 is an equidigital number, since it uses as much as digits as its factorization.

645217437 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48048 (or 47981 counting only the distinct ones).

The product of its digits is 141120, while the sum is 39.

The square root of 645217437 is about 25401.1306244427. The cubic root of 645217437 is about 864.1093383897.

The spelling of 645217437 in words is "six hundred forty-five million, two hundred seventeen thousand, four hundred thirty-seven".