213665551 has 6 divisors (see below), whose sum is σ = 234855656. Its totient is φ = 194241300.

The previous prime is 213665527. The next prime is 213665567. The reversal of 213665551 is 155566312.

It is not a de Polignac number, because 213665551 - 2⁵ = 213665519 is a prime.

It is a Duffinian number.

It is a zygodrome in base 6.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213665651) 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, 882795 + ... + 883036.

Almost surely, 2^213665551 is an apocalyptic number.

213665551 is a deficient number, since it is larger than the sum of its proper divisors (21190105).

213665551 is a wasteful number, since it uses less digits than its factorization.

213665551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1765853 (or 1765842 counting only the distinct ones).

The product of its digits is 27000, while the sum is 34.

The square root of 213665551 is about 14617.3031370359. The cubic root of 213665551 is about 597.8306390564.

The spelling of 213665551 in words is "two hundred thirteen million, six hundred sixty-five thousand, five hundred fifty-one".