645436331402 has 4 divisors (see below), whose sum is σ = 968154497106. Its totient is φ = 322718165700.

The previous prime is 645436331369. The next prime is 645436331437. The reversal of 645436331402 is 204133634546.

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

It can be written as a sum of positive squares in only one way, i.e., 631451140321 + 13985191081 = 794639^2 + 118259^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 645436331402.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161359082849 + ... + 161359082852.

Almost surely, 2^645436331402 is an apocalyptic number.

645436331402 is a deficient number, since it is larger than the sum of its proper divisors (322718165704).

645436331402 is a wasteful number, since it uses less digits than its factorization.

645436331402 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 322718165703.

The product of its (nonzero) digits is 622080, while the sum is 41.

Adding to 645436331402 its reverse (204133634546), we get a palindrome (849569965948).

The spelling of 645436331402 in words is "six hundred forty-five billion, four hundred thirty-six million, three hundred thirty-one thousand, four hundred two".