645520101 has 8 divisors (see below), whose sum is σ = 866176224. Its totient is φ = 427605360.

The previous prime is 645520091. The next prime is 645520129. The reversal of 645520101 is 101025546.

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

It is not a de Polignac number, because 645520101 - 2¹⁵ = 645487333 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645520151) 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, 684795 + ... + 685736.

It is an arithmetic number, because the mean of its divisors is an integer number (108272028).

Almost surely, 2^645520101 is an apocalyptic number.

It is an amenable number.

645520101 is a deficient number, since it is larger than the sum of its proper divisors (220656123).

645520101 is a wasteful number, since it uses less digits than its factorization.

645520101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1370691.

The product of its (nonzero) digits is 1200, while the sum is 24.

The square root of 645520101 is about 25407.0876134987. The cubic root of 645520101 is about 864.2444318172.

Adding to 645520101 its reverse (101025546), we get a palindrome (746545647).

The spelling of 645520101 in words is "six hundred forty-five million, five hundred twenty thousand, one hundred one".