645442157 has 2 divisors, whose sum is σ = 645442158. Its totient is φ = 645442156.

The previous prime is 645442153. The next prime is 645442177. The reversal of 645442157 is 751244546.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 558187876 + 87254281 = 23626^2 + 9341^2 .

It is a cyclic number.

It is not a de Polignac number, because 645442157 - 2² = 645442153 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 645442157.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (645442153) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322721078 + 322721079.

It is an arithmetic number, because the mean of its divisors is an integer number (322721079).

Almost surely, 2^645442157 is an apocalyptic number.

It is an amenable number.

645442157 is a deficient number, since it is larger than the sum of its proper divisors (1).

645442157 is an equidigital number, since it uses as much as digits as its factorization.

645442157 is an evil number, because the sum of its binary digits is even.

The product of its digits is 134400, while the sum is 38.

The square root of 645442157 is about 25405.5536645041. The cubic root of 645442157 is about 864.2096457177.

The spelling of 645442157 in words is "six hundred forty-five million, four hundred forty-two thousand, one hundred fifty-seven".