211216551 has 64 divisors (see below), whose sum is σ = 372750336. Its totient is φ = 103219200.

The previous prime is 211216531. The next prime is 211216591. The reversal of 211216551 is 155612112.

It is not a de Polignac number, because 211216551 - 2¹³ = 211208359 is a prime.

It is a super-2 number, since 2×211216551² = 89224862832671202, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211216531) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 329191 + ... + 329831.

It is an arithmetic number, because the mean of its divisors is an integer number (5824224).

Almost surely, 2^211216551 is an apocalyptic number.

211216551 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

211216551 is a deficient number, since it is larger than the sum of its proper divisors (161533785).

211216551 is a wasteful number, since it uses less digits than its factorization.

211216551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 752.

The product of its digits is 600, while the sum is 24.

The square root of 211216551 is about 14533.2911276146. The cubic root of 211216551 is about 595.5377771014.

Adding to 211216551 its reverse (155612112), we get a palindrome (366828663).

It can be divided in two parts, 21121 and 6551, that added together give a palindrome (27672).

The spelling of 211216551 in words is "two hundred eleven million, two hundred sixteen thousand, five hundred fifty-one".