661464861 has 4 divisors (see below), whose sum is σ = 881953152. Its totient is φ = 440976572.

The previous prime is 661464833. The next prime is 661464877. The reversal of 661464861 is 168464166.

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 661464861 - 2¹³ = 661456669 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661464361) 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, 110244141 + ... + 110244146.

It is an arithmetic number, because the mean of its divisors is an integer number (220488288).

Almost surely, 2^661464861 is an apocalyptic number.

It is an amenable number.

661464861 is a deficient number, since it is larger than the sum of its proper divisors (220488291).

661464861 is a wasteful number, since it uses less digits than its factorization.

661464861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 220488290.

The product of its digits is 165888, while the sum is 42.

The square root of 661464861 is about 25718.9591741190. The cubic root of 661464861 is about 871.3024315738.

The spelling of 661464861 in words is "six hundred sixty-one million, four hundred sixty-four thousand, eight hundred sixty-one".