645133512031 has 4 divisors (see below), whose sum is σ = 645628627312. Its totient is φ = 644638396752.

The previous prime is 645133511927. The next prime is 645133512061. The reversal of 645133512031 is 130215331546.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-645133512031 is a prime.

It is a super-2 number, since 2×645133512031² (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 (645133512061) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 247555686 + ... + 247558291.

It is an arithmetic number, because the mean of its divisors is an integer number (161407156828).

Almost surely, 2^645133512031 is an apocalyptic number.

645133512031 is a deficient number, since it is larger than the sum of its proper divisors (495115281).

645133512031 is a wasteful number, since it uses less digits than its factorization.

645133512031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 495115280.

The product of its (nonzero) digits is 32400, while the sum is 34.

Adding to 645133512031 its reverse (130215331546), we get a palindrome (775348843577).

The spelling of 645133512031 in words is "six hundred forty-five billion, one hundred thirty-three million, five hundred twelve thousand, thirty-one".