661863903 has 8 divisors (see below), whose sum is σ = 883038768. Its totient is φ = 440965824.

The previous prime is 661863899. The next prime is 661863913. The reversal of 661863903 is 309368166.

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

It is not a de Polignac number, because 661863903 - 2² = 661863899 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661863913) 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, 63550 + ... + 73227.

It is an arithmetic number, because the mean of its divisors is an integer number (110379846).

Almost surely, 2^661863903 is an apocalyptic number.

661863903 is a deficient number, since it is larger than the sum of its proper divisors (221174865).

661863903 is a wasteful number, since it uses less digits than its factorization.

661863903 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 138393.

The product of its (nonzero) digits is 139968, while the sum is 42.

The square root of 661863903 is about 25726.7157445330. The cubic root of 661863903 is about 871.4776065995.

The spelling of 661863903 in words is "six hundred sixty-one million, eight hundred sixty-three thousand, nine hundred three".