645516161 has 4 divisors (see below), whose sum is σ = 645711024. Its totient is φ = 645321300.

The previous prime is 645516107. The next prime is 645516169. The reversal of 645516161 is 161615546.

645516161 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-645516161 is a prime.

It is a super-2 number, since 2×645516161² = 833382228224355842, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (645516169) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 92375 + ... + 99116.

It is an arithmetic number, because the mean of its divisors is an integer number (161427756).

Almost surely, 2^645516161 is an apocalyptic number.

It is an amenable number.

645516161 is a deficient number, since it is larger than the sum of its proper divisors (194863).

645516161 is a wasteful number, since it uses less digits than its factorization.

645516161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 194862.

The product of its digits is 21600, while the sum is 35.

The square root of 645516161 is about 25407.0100759613. The cubic root of 645516161 is about 864.2426734779.

The spelling of 645516161 in words is "six hundred forty-five million, five hundred sixteen thousand, one hundred sixty-one".