661111582 has 4 divisors (see below), whose sum is σ = 991667376. Its totient is φ = 330555790.

The previous prime is 661111573. The next prime is 661111603. The reversal of 661111582 is 285111166.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 285111166 = 2 ⋅142555583.

It is a congruent number.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 165277894 + ... + 165277897.

It is an arithmetic number, because the mean of its divisors is an integer number (247916844).

Almost surely, 2^661111582 is an apocalyptic number.

661111582 is a deficient number, since it is larger than the sum of its proper divisors (330555794).

661111582 is a wasteful number, since it uses less digits than its factorization.

661111582 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 330555793.

The product of its digits is 2880, while the sum is 31.

The square root of 661111582 is about 25712.0901911922. The cubic root of 661111582 is about 871.1472871937.

The spelling of 661111582 in words is "six hundred sixty-one million, one hundred eleven thousand, five hundred eighty-two".