661847863 has 4 divisors (see below), whose sum is σ = 661970008. Its totient is φ = 661725720.

The previous prime is 661847833. The next prime is 661847867. The reversal of 661847863 is 368748166.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 661847863 - 2¹⁷ = 661716791 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661847867) 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, 52548 + ... + 63913.

It is an arithmetic number, because the mean of its divisors is an integer number (165492502).

Almost surely, 2^661847863 is an apocalyptic number.

661847863 is a deficient number, since it is larger than the sum of its proper divisors (122145).

661847863 is a wasteful number, since it uses less digits than its factorization.

661847863 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 122144.

The product of its digits is 1161216, while the sum is 49.

The square root of 661847863 is about 25726.4040044465. The cubic root of 661847863 is about 871.4705665752.

It can be divided in two parts, 66184 and 7863, that added together give a palindrome (74047).

The spelling of 661847863 in words is "six hundred sixty-one million, eight hundred forty-seven thousand, eight hundred sixty-three".