661424805 has 16 divisors (see below), whose sum is σ = 1175866560. Its totient is φ = 352759824.

The previous prime is 661424791. The next prime is 661424807. The reversal of 661424805 is 508424166.

661424805 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 661424805 - 2⁷ = 661424677 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 661424805.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661424807) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2449587 + ... + 2449856.

It is an arithmetic number, because the mean of its divisors is an integer number (73491660).

Almost surely, 2^661424805 is an apocalyptic number.

It is an amenable number.

661424805 is a deficient number, since it is larger than the sum of its proper divisors (514441755).

661424805 is a wasteful number, since it uses less digits than its factorization.

661424805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4899457 (or 4899451 counting only the distinct ones).

The product of its (nonzero) digits is 46080, while the sum is 36.

The square root of 661424805 is about 25718.1804371927. The cubic root of 661424805 is about 871.2848435421.

The spelling of 661424805 in words is "six hundred sixty-one million, four hundred twenty-four thousand, eight hundred five".