645473181 has 8 divisors (see below), whose sum is σ = 863347104. Its totient is φ = 428957360.

The previous prime is 645473161. The next prime is 645473201. The reversal of 645473181 is 181374546.

It is an interprime number because it is at equal distance from previous prime (645473161) and next prime (645473201).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 645473181 - 2⁶ = 645473117 is a prime.

It is a super-2 number, since 2×645473181² = 833271254780517522, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645473131) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 338415 + ... + 340316.

It is an arithmetic number, because the mean of its divisors is an integer number (107918388).

Almost surely, 2^645473181 is an apocalyptic number.

It is an amenable number.

645473181 is a deficient number, since it is larger than the sum of its proper divisors (217873923).

645473181 is a wasteful number, since it uses less digits than its factorization.

645473181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 679051.

The product of its digits is 80640, while the sum is 39.

The square root of 645473181 is about 25406.1642323276. The cubic root of 645473181 is about 864.2234919419.

The spelling of 645473181 in words is "six hundred forty-five million, four hundred seventy-three thousand, one hundred eighty-one".