661447077 has 4 divisors (see below), whose sum is σ = 881929440. Its totient is φ = 440964716.

The previous prime is 661447069. The next prime is 661447099. The reversal of 661447077 is 770744166.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 661447077 - 2³ = 661447069 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661447177) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 110241177 + ... + 110241182.

It is an arithmetic number, because the mean of its divisors is an integer number (220482360).

Almost surely, 2^661447077 is an apocalyptic number.

It is an amenable number.

661447077 is a deficient number, since it is larger than the sum of its proper divisors (220482363).

661447077 is a wasteful number, since it uses less digits than its factorization.

661447077 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 220482362.

The product of its (nonzero) digits is 197568, while the sum is 42.

The square root of 661447077 is about 25718.6134346313. The cubic root of 661447077 is about 871.2946229547.

The spelling of 661447077 in words is "six hundred sixty-one million, four hundred forty-seven thousand, seventy-seven".