656271987811 has 4 divisors (see below), whose sum is σ = 715933077624. Its totient is φ = 596610898000.

The previous prime is 656271987719. The next prime is 656271987817. The reversal of 656271987811 is 118789172656.

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 656271987811 - 2²⁷ = 656137770083 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 656271987811.

It is not an unprimeable number, because it can be changed into a prime (656271987817) 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, 29830544890 + ... + 29830544911.

It is an arithmetic number, because the mean of its divisors is an integer number (178983269406).

Almost surely, 2^656271987811 is an apocalyptic number.

656271987811 is a deficient number, since it is larger than the sum of its proper divisors (59661089813).

656271987811 is a wasteful number, since it uses less digits than its factorization.

656271987811 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59661089812.

The product of its digits is 10160640, while the sum is 61.

The spelling of 656271987811 in words is "six hundred fifty-six billion, two hundred seventy-one million, nine hundred eighty-seven thousand, eight hundred eleven".