671863905 has 12 divisors (see below), whose sum is σ = 1164564180. Its totient is φ = 358327392.

The previous prime is 671863903. The next prime is 671863939. The reversal of 671863905 is 509368176.

It is a happy number.

671863905 is a `hidden beast` number, since 6 + 7 + 1 + 8 + 639 + 0 + 5 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 403166241 + 268697664 = 20079^2 + 16392^2 .

It is not a de Polignac number, because 671863905 - 2¹ = 671863903 is a prime.

It is a super-2 number, since 2×671863905² = 902802213683698050, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45), and also a Moran number because the ratio is a prime number: 14930309 = 671863905 / (6 + 7 + 1 + 8 + 6 + 3 + 9 + 0 + 5).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (671863903) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7465110 + ... + 7465199.

It is an arithmetic number, because the mean of its divisors is an integer number (97047015).

Almost surely, 2^671863905 is an apocalyptic number.

It is an amenable number.

671863905 is a deficient number, since it is larger than the sum of its proper divisors (492700275).

671863905 is a wasteful number, since it uses less digits than its factorization.

671863905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14930320 (or 14930317 counting only the distinct ones).

The product of its (nonzero) digits is 272160, while the sum is 45.

The square root of 671863905 is about 25920.3376714116. The cubic root of 671863905 is about 875.8446939599.

The spelling of 671863905 in words is "six hundred seventy-one million, eight hundred sixty-three thousand, nine hundred five".