645131102121 has 96 divisors (see below), whose sum is σ = 1094138438400. Its totient is φ = 375058252800.

The previous prime is 645131102113. The next prime is 645131102129. The reversal of 645131102121 is 121201131546.

645131102121 is a `hidden beast` number, since 645 + 1 + 3 + 1 + 1 + 0 + 2 + 12 + 1 = 666.

It is an interprime number because it is at equal distance from previous prime (645131102113) and next prime (645131102129).

It is not a de Polignac number, because 645131102121 - 2³ = 645131102113 is a prime.

It is a super-2 number, since 2×645131102121² (a number of 24 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (645131102129) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 8544825 + ... + 8619993.

It is an arithmetic number, because the mean of its divisors is an integer number (11397275400).

Almost surely, 2^645131102121 is an apocalyptic number.

It is an amenable number.

645131102121 is a deficient number, since it is larger than the sum of its proper divisors (449007336279).

645131102121 is a wasteful number, since it uses less digits than its factorization.

645131102121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75308 (or 75291 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 27.

Adding to 645131102121 its reverse (121201131546), we get a palindrome (766332233667).

The spelling of 645131102121 in words is "six hundred forty-five billion, one hundred thirty-one million, one hundred two thousand, one hundred twenty-one".