645122641 has 16 divisors (see below), whose sum is σ = 666921600. Its totient is φ = 623779200.

The previous prime is 645122633. The next prime is 645122689. The reversal of 645122641 is 146221546.

It is a happy number.

645122641 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 645122641 - 2³ = 645122633 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (645122041) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1796820 + ... + 1797178.

It is an arithmetic number, because the mean of its divisors is an integer number (41682600).

Almost surely, 2^645122641 is an apocalyptic number.

645122641 is a gapful number since it is divisible by the number (61) formed by its first and last digit.

It is an amenable number.

645122641 is a deficient number, since it is larger than the sum of its proper divisors (21798959).

645122641 is a wasteful number, since it uses less digits than its factorization.

645122641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 840.

The product of its digits is 11520, while the sum is 31.

The square root of 645122641 is about 25399.2645759675. The cubic root of 645122641 is about 864.0670177103.

It can be divided in two parts, 6451 and 22641, that added together give a palindrome (29092).

The spelling of 645122641 in words is "six hundred forty-five million, one hundred twenty-two thousand, six hundred forty-one".