661904203 has 4 divisors (see below), whose sum is σ = 677297368. Its totient is φ = 646511040.

The previous prime is 661904183. The next prime is 661904209. The reversal of 661904203 is 302409166.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 302409166 = 2 ⋅151204583.

It is a cyclic number.

It is not a de Polignac number, because 661904203 - 2⁹ = 661903691 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661904209) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7696518 + ... + 7696603.

It is an arithmetic number, because the mean of its divisors is an integer number (169324342).

Almost surely, 2^661904203 is an apocalyptic number.

661904203 is a deficient number, since it is larger than the sum of its proper divisors (15393165).

661904203 is a wasteful number, since it uses less digits than its factorization.

661904203 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15393164.

The product of its (nonzero) digits is 7776, while the sum is 31.

The square root of 661904203 is about 25727.4989651151. The cubic root of 661904203 is about 871.4952939390.

The spelling of 661904203 in words is "six hundred sixty-one million, nine hundred four thousand, two hundred three".