661220567 has 4 divisors (see below), whose sum is σ = 755680656. Its totient is φ = 566760480.

The previous prime is 661220563. The next prime is 661220569. The reversal of 661220567 is 765022166.

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 661220567 - 2² = 661220563 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 (661220563) 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, 47230034 + ... + 47230047.

It is an arithmetic number, because the mean of its divisors is an integer number (188920164).

Almost surely, 2^661220567 is an apocalyptic number.

661220567 is a deficient number, since it is larger than the sum of its proper divisors (94460089).

661220567 is an equidigital number, since it uses as much as digits as its factorization.

661220567 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 94460088.

The product of its (nonzero) digits is 30240, while the sum is 35.

The square root of 661220567 is about 25714.2094375853. The cubic root of 661220567 is about 871.1951544388.

The spelling of 661220567 in words is "six hundred sixty-one million, two hundred twenty thousand, five hundred sixty-seven".