213481856665 has 108 divisors (see below), whose sum is σ = 342443261412. Its totient is φ = 127284178560.

The previous prime is 213481856597. The next prime is 213481856669. The reversal of 213481856665 is 566658184312.

It can be written as a sum of positive squares in 2 ways, for example, as 22130727696 + 191351128969 = 148764^2 + 437437^2 .

It is not a de Polignac number, because 213481856665 - 2⁹ = 213481856153 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (55).

It is not an unprimeable number, because it can be changed into a prime (213481856669) by changing a digit.

It is a polite number, since it can be written in 107 ways as a sum of consecutive naturals, for example, 15675399 + ... + 15689011.

It is an arithmetic number, because the mean of its divisors is an integer number (3170770939).

Almost surely, 2^213481856665 is an apocalyptic number.

It is an amenable number.

213481856665 is a deficient number, since it is larger than the sum of its proper divisors (128961404747).

213481856665 is a wasteful number, since it uses less digits than its factorization.

213481856665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13700 (or 13659 counting only the distinct ones).

The product of its digits is 8294400, while the sum is 55.

The spelling of 213481856665 in words is "two hundred thirteen billion, four hundred eighty-one million, eight hundred fifty-six thousand, six hundred sixty-five".