645741442 has 4 divisors (see below), whose sum is σ = 968612166. Its totient is φ = 322870720.

The previous prime is 645741409. The next prime is 645741443. The reversal of 645741442 is 244147546.

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., 634989601 + 10751841 = 25199^2 + 3279^2 .

It is not an unprimeable number, because it can be changed into a prime (645741443) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161435359 + ... + 161435362.

Almost surely, 2^645741442 is an apocalyptic number.

645741442 is a deficient number, since it is larger than the sum of its proper divisors (322870724).

645741442 is a wasteful number, since it uses less digits than its factorization.

645741442 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 322870723.

The product of its digits is 107520, while the sum is 37.

The square root of 645741442 is about 25411.4431309991. The cubic root of 645741442 is about 864.3432001678.

Adding to 645741442 its reverse (244147546), we get a palindrome (889888988).

The spelling of 645741442 in words is "six hundred forty-five million, seven hundred forty-one thousand, four hundred forty-two".