213351561 has 6 divisors (see below), whose sum is σ = 308174490. Its totient is φ = 142234368.

The previous prime is 213351559. The next prime is 213351563. The reversal of 213351561 is 165153312.

213351561 is a `hidden beast` number, since 21 + 33 + 51 + 561 = 666.

It is an interprime number because it is at equal distance from previous prime (213351559) and next prime (213351563).

It can be written as a sum of positive squares in only one way, i.e., 209525625 + 3825936 = 14475^2 + 1956^2 .

It is not a de Polignac number, because 213351561 - 2¹ = 213351559 is a prime.

It is a super-2 number, since 2×213351561² = 91037777162273442, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (213351563) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 11852856 + ... + 11852873.

It is an arithmetic number, because the mean of its divisors is an integer number (51362415).

Almost surely, 2^213351561 is an apocalyptic number.

It is an amenable number.

213351561 is a deficient number, since it is larger than the sum of its proper divisors (94822929).

213351561 is a wasteful number, since it uses less digits than its factorization.

213351561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23705735 (or 23705732 counting only the distinct ones).

The product of its digits is 2700, while the sum is 27.

The square root of 213351561 is about 14606.5588349892. The cubic root of 213351561 is about 597.5376502129.

The spelling of 213351561 in words is "two hundred thirteen million, three hundred fifty-one thousand, five hundred sixty-one".