661630406 has 4 divisors (see below), whose sum is σ = 992445612. Its totient is φ = 330815202.

The previous prime is 661630381. The next prime is 661630423. The reversal of 661630406 is 604036166.

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

It is a congruent number.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 165407600 + ... + 165407603.

It is an arithmetic number, because the mean of its divisors is an integer number (248111403).

Almost surely, 2^661630406 is an apocalyptic number.

661630406 is a deficient number, since it is larger than the sum of its proper divisors (330815206).

661630406 is a wasteful number, since it uses less digits than its factorization.

661630406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 330815205.

The product of its (nonzero) digits is 15552, while the sum is 32.

The square root of 661630406 is about 25722.1773184153. The cubic root of 661630406 is about 871.3751125471.

The spelling of 661630406 in words is "six hundred sixty-one million, six hundred thirty thousand, four hundred six".