645436331437 has 2 divisors, whose sum is σ = 645436331438. Its totient is φ = 645436331436.

The previous prime is 645436331369. The next prime is 645436331443. The reversal of 645436331437 is 734133634546.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 631824675876 + 13611655561 = 794874^2 + 116669^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-645436331437 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (645436331447) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322718165718 + 322718165719.

It is an arithmetic number, because the mean of its divisors is an integer number (322718165719).

Almost surely, 2^645436331437 is an apocalyptic number.

It is an amenable number.

645436331437 is a deficient number, since it is larger than the sum of its proper divisors (1).

645436331437 is an equidigital number, since it uses as much as digits as its factorization.

645436331437 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6531840, while the sum is 49.

The spelling of 645436331437 in words is "six hundred forty-five billion, four hundred thirty-six million, three hundred thirty-one thousand, four hundred thirty-seven".