213567561 has 6 divisors (see below), whose sum is σ = 308486490. Its totient is φ = 142378368.

The previous prime is 213567553. The next prime is 213567569. The reversal of 213567561 is 165765312.

213567561 is a `hidden beast` number, since 2 + 1 + 35 + 67 + 561 = 666.

It is an interprime number because it is at equal distance from previous prime (213567553) and next prime (213567569).

It can be written as a sum of positive squares in only one way, i.e., 213014025 + 553536 = 14595^2 + 744^2 .

It is not a de Polignac number, because 213567561 - 2³ = 213567553 is a prime.

It is a super-2 number, since 2×213567561² = 91222206222977442, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (213567569) by changing a digit.

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 5 ways as a sum of consecutive naturals, for example, 11864856 + ... + 11864873.

It is an arithmetic number, because the mean of its divisors is an integer number (51414415).

Almost surely, 2^213567561 is an apocalyptic number.

It is an amenable number.

213567561 is a deficient number, since it is larger than the sum of its proper divisors (94918929).

213567561 is a wasteful number, since it uses less digits than its factorization.

213567561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23729735 (or 23729732 counting only the distinct ones).

The product of its digits is 37800, while the sum is 36.

The square root of 213567561 is about 14613.9509031610. The cubic root of 213567561 is about 597.7392339269.

It can be divided in two parts, 2135 and 67561, that added together give a palindrome (69696).

The spelling of 213567561 in words is "two hundred thirteen million, five hundred sixty-seven thousand, five hundred sixty-one".