661563479 has 4 divisors (see below), whose sum is σ = 661676400. Its totient is φ = 661450560.

The previous prime is 661563431. The next prime is 661563491. The reversal of 661563479 is 974365166.

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 661563479 - 2¹⁶ = 661497943 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 (661563499) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 47162 + ... + 59559.

It is an arithmetic number, because the mean of its divisors is an integer number (165419100).

Almost surely, 2^661563479 is an apocalyptic number.

661563479 is a deficient number, since it is larger than the sum of its proper divisors (112921).

661563479 is a wasteful number, since it uses less digits than its factorization.

661563479 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 112920.

The product of its digits is 816480, while the sum is 47.

The square root of 661563479 is about 25720.8763264396. The cubic root of 661563479 is about 871.3457303381.

The spelling of 661563479 in words is "six hundred sixty-one million, five hundred sixty-three thousand, four hundred seventy-nine".