216721274 has 16 divisors (see below), whose sum is σ = 405297216. Its totient is φ = 84436800.

The previous prime is 216721261. The next prime is 216721343. The reversal of 216721274 is 472127612.

It is a super-2 number, since 2×216721274² = 93936221208366152, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a self number, because there is not a number n which added to its sum of digits gives 216721274.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 703487 + ... + 703794.

It is an arithmetic number, because the mean of its divisors is an integer number (25331076).

Almost surely, 2^216721274 is an apocalyptic number.

216721274 is a deficient number, since it is larger than the sum of its proper divisors (188575942).

216721274 is a wasteful number, since it uses less digits than its factorization.

216721274 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1407301.

The product of its digits is 9408, while the sum is 32.

The square root of 216721274 is about 14721.4562459018. The cubic root of 216721274 is about 600.6671043078.

Adding to 216721274 its reverse (472127612), we get a palindrome (688848886).

The spelling of 216721274 in words is "two hundred sixteen million, seven hundred twenty-one thousand, two hundred seventy-four".