645616737 has 24 divisors (see below), whose sum is σ = 993248256. Its totient is φ = 418772592.

The previous prime is 645616711. The next prime is 645616801. The reversal of 645616737 is 737616546.

645616737 is a `hidden beast` number, since 6 + 456 + 167 + 37 = 666.

645616737 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 645616737 - 2¹⁴ = 645600353 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 645616692 and 645616701.

It is not an unprimeable number, because it can be changed into a prime (645636737) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 26913 + ... + 44894.

It is an arithmetic number, because the mean of its divisors is an integer number (41385344).

Almost surely, 2^645616737 is an apocalyptic number.

It is an amenable number.

645616737 is a deficient number, since it is larger than the sum of its proper divisors (347631519).

645616737 is an equidigital number, since it uses as much as digits as its factorization.

645616737 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71859 (or 71847 counting only the distinct ones).

The product of its digits is 635040, while the sum is 45.

The square root of 645616737 is about 25408.9892951294. The cubic root of 645616737 is about 864.2875561947.

The spelling of 645616737 in words is "six hundred forty-five million, six hundred sixteen thousand, seven hundred thirty-seven".