1661581586 has 32 divisors (see below), whose sum is σ = 2951949312. Its totient is φ = 686407680.

The previous prime is 1661581577. The next prime is 1661581591. The reversal of 1661581586 is 6851851661.

It is a self number, because there is not a number n which added to its sum of digits gives 1661581586.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 104090 + ... + 118986.

It is an arithmetic number, because the mean of its divisors is an integer number (92248416).

Almost surely, 2^1661581586 is an apocalyptic number.

1661581586 is a deficient number, since it is larger than the sum of its proper divisors (1290367726).

1661581586 is a wasteful number, since it uses less digits than its factorization.

1661581586 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15194.

The product of its digits is 345600, while the sum is 47.

The square root of 1661581586 is about 40762.5022048451. The cubic root of 1661581586 is about 1184.4240671313.

The spelling of 1661581586 in words is "one billion, six hundred sixty-one million, five hundred eighty-one thousand, five hundred eighty-six".