645541031 has 2 divisors, whose sum is σ = 645541032. Its totient is φ = 645541030.

The previous prime is 645541009. The next prime is 645541033. The reversal of 645541031 is 130145546.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 645541031 - 2⁶ = 645540967 is a prime.

It is a super-2 number, since 2×645541031² = 833446445409085922, which contains 22 as substring.

Together with 645541033, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 645540985 and 645541003.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (645541033) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322770515 + 322770516.

It is an arithmetic number, because the mean of its divisors is an integer number (322770516).

Almost surely, 2^645541031 is an apocalyptic number.

645541031 is a deficient number, since it is larger than the sum of its proper divisors (1).

645541031 is an equidigital number, since it uses as much as digits as its factorization.

645541031 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7200, while the sum is 29.

The square root of 645541031 is about 25407.4995030995. The cubic root of 645541031 is about 864.2537723166.

Adding to 645541031 its reverse (130145546), we get a palindrome (775686577).

The spelling of 645541031 in words is "six hundred forty-five million, five hundred forty-one thousand, thirty-one".