645834921 has 8 divisors (see below), whose sum is σ = 861552000. Its totient is φ = 430337232.

The previous prime is 645834907. The next prime is 645834929. The reversal of 645834921 is 129438546.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 645834921 - 2⁶ = 645834857 is a prime.

It is not an unprimeable number, because it can be changed into a prime (645834929) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 47850 + ... + 59843.

It is an arithmetic number, because the mean of its divisors is an integer number (107694000).

Almost surely, 2^645834921 is an apocalyptic number.

It is an amenable number.

645834921 is a deficient number, since it is larger than the sum of its proper divisors (215717079).

645834921 is a wasteful number, since it uses less digits than its factorization.

645834921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 109695.

The product of its digits is 207360, while the sum is 42.

The square root of 645834921 is about 25413.2823735935. The cubic root of 645834921 is about 864.3849062513.

The spelling of 645834921 in words is "six hundred forty-five million, eight hundred thirty-four thousand, nine hundred twenty-one".