645122125021 has 8 divisors (see below), whose sum is σ = 703837043424. Its totient is φ = 586418448720.

The previous prime is 645122124991. The next prime is 645122125091. The reversal of 645122125021 is 120521221546.

645122125021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is not a de Polignac number, because 645122125021 - 2¹⁹ = 645121600733 is a prime.

It is a super-2 number, since 2×645122125021² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645122125091) 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, 2690311 + ... + 2920276.

It is an arithmetic number, because the mean of its divisors is an integer number (87979630428).

Almost surely, 2^645122125021 is an apocalyptic number.

It is an amenable number.

645122125021 is a deficient number, since it is larger than the sum of its proper divisors (58714918403).

645122125021 is a wasteful number, since it uses less digits than its factorization.

645122125021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5621051.

The product of its (nonzero) digits is 9600, while the sum is 31.

Adding to 645122125021 its reverse (120521221546), we get a palindrome (765643346567).

The spelling of 645122125021 in words is "six hundred forty-five billion, one hundred twenty-two million, one hundred twenty-five thousand, twenty-one".